Yes, those are possibilities for tactical summons. Tactical summons will be weaker than strategic summons, but they can have other effects such as what you suggested.  For now I've jotted down that it has chaos-esque procs from its melee attacks.

Added.

have ya'll thought about pulling out tha ol' D&D Monster manuels?  There be a ton of interesting creatures with well thought out abilities (not all, but most/ never liked the square & rectangle looking enemies except for maybe the 'monster chest', looks like a treasure chest but is actually a monster using an illusion). 

What about an ant liner / ant lion (can't remember tha right name), the little bugs that create a funnel in tha sand, then an ant (or anything of equalish size) comes walkin by & falls in, the sand is too slick for the ant to climb very well and the ant lion will toss sand up on the ant to make it lose it's footing & fall down to the bottom/center where the ant lion dwells, at which time the ant is grabbed and smashed against the sides of the 'cone' over & over again to stun it, then takes it under the sand to smother it

What about pheramons (spelling?), say when you pick up an ant & then drop him back on the ant bed, the other ants that he comes into contact with or get around go crazy & into attack mode.  Same thing with bees & others.  Or perhaps the blood frenzy type thing sharks have giving the creatures affected bonuses/negatives

What about an abnormally Large Embred dragon (or Titan or something) that eats everything within his territory/hunting grounds, meaning neutrals/faction members/resources you name it, growing stronger and larger with everything he consumes, once everything that can be consumed in his territory is, he will then begin to 'wander' in search of new 'resources'.  I was thinkin this would be treated like a wildland up to the point where he begins to roam in Late game.

What about them worms on Tremors, something that moves underground & therefore can only be beaten when it attacks it's prey (can't move through water/swamps?), and it creats another each battle if it's victorious - should attack all living things (neutrals included)

Summons/creatures/other (Just brainstormin, maybe something will be of use?):

Madusa/Gorgon/Basilisk - (heh, think of getting Madusa's head as a trophy that can be carried around & used to stone your opponents)

Gargoyle (Cast on city or outpost as 'militia')

lycanthropy (anything attacked by a Werewolf/bear/shark/etc. would have a % chance of becoming infected & switching sides)

Vampires (can charm & cause one unit to move towards it in tac battle unless the unit resist, has regen, can cast escape self)

Lich/Demi Lich - level drain ability upon contact, Demi Lich being Archmage that survived death through magic= ultra powerfull spell caster

Mummie - High lvl get spell casting ability to go with there high constitution/strength

skeletons - normall 1d6 nothings, high lvl gain large attack/dodge bonuses, normally controlled/animated by 'higher power'

nightmare ('undead' horse- can breath fire upon lvl up &/or units take fire damage upon contact)

stirges (Giant mesquitos, this is how I lost my 2nd lvl1 character in D&D) - Picture right after a hurricane, the mesquitoes block out tha sun, those B*st*rds are scarey, now think of them the size of a football

griffen (Bonuses to fighting dragon kind)

manitcore (lion head/body, wings of a bat, & tail of scorpion)

owlbear - never really liked this one, but it came to my mind

bugbear - semi-intelligent 2 leggers that look hairy & have decent constitution & strength & shamans/clerics

ghoul (Can't really remember which undead get which draining abilities: drain hp, lvls, certain attributes, etc.)

ghast

specter

ghost

wight - killing a unit produces a certain amount of amount of undead warriors (depending on lvl of victums: lvl 1- skeletons would be produced, lvl 2- zombies, lvl 3- ghasts, lvl 4- vampire, lvl 5- lich etc.) - not sure if this should happen during tac battle or strat map

wraith

orcs - equall to humans in most ways but normally a bit stronger/tougher

goblins - lots  & lots of cheap cheap cannon fodder, with the ability to have shamans & such, can be found most anywhere

lizardmen - don't normally travell further from water than about one turn's movements worth, will continue to grow settlements along riverways/ponds/lakes

mermen - these guys can really hold there breath, can have shamans & such

drow (elves) - underground darker versions of elves

barbarian - totem worshipin savages, always causing problems

ettin (two headed giant)

hill giant - normally wearin an over tha shoulder boulder holder

fire giant - these guys are flamin

storm giant - where lightening comes from

cloud giant - anyone have any magic beans?

frost giant - frigid B*tches

giant rats - uhm.., larger than normall rodents

kobalds (small humaniod lizard peeps, can have shamans & such, like to dwell in sewers & caves)

elves - a bunch'a tree huggers

dwarves - cave dwelling stout midgets that love ale & stone

ogre - Big dummies that like petting rodents & eating other humaniods, on occasion will have a shaman/cleric

nymph (Charm spell, normally found in forests)

Highwaymen (Cast on strat map to creat neutral bandits that don't attack you, possibly they could give you a % of there take)

troll (might be nice for bridges to have some kind of trollish resident) - I think trolls & regen characters defeated in a tac battle should return to life once the battle is over unless fire/lightening/acid is used in it's death

umberhulk (cave making/dwelling, hard shelled apes?)

sloth demon - Lazy

pride demon - General Custer at the battle of little big horn or sitting bull or something

rage demon - See under Succubus

desire demon - Also see under Succubus

changling/or dopleganger (creatures able to take the form of a 'human')

succubus (my wife)

halfling - short people that love to smoke tha goodness & eat alot

witch - My stepmother, scared of water

warlock - love it when you hammer nails into their footprints

hell hounds (if in melee attacker/defender takes fire damage upon succesfull strike)

hydra (if damaged to 75% and it survives it gains another head, gaining another recovering from 50%, and another from 25% - has regen & waterwalk)

Kraken (Percentage chance to kill unit on hit, massive constitution, immune to water spells, restricted to water)

minataur - I recall a certain story of a 'minataur's maze' over in the mediteranean back in tha old days

smurfs (upon killing a smurf, attacker gains 5-20? mana - only visible if in square adjacent (village can only be seen by 'walkin' into its square) - each smurf skin obtained/used allows for double the power of any given spell or enchantment (one use per skin of course)

cyclops (accuracy penalty, gains +1 strength/constitution upon every kill/meal, like to herd sheep)

draconians (Have random effect upon death: -turn to stone, which will take away the attackers weapon if piercing/slashing - explode, the draconian explodes - (d*mmit can't remember the other ways)), gain +1 movement when moving off hills due to most being able to glide but not fly

slimes (50% chance to duplicate when struck by slashing weapons with no damage taken, half damage from piercing with 15%? chance of duplication, & double damage from blunt attacks with no chance of duplication), some are poisonus, higher lvl allows them to spit poison & gain greater ac

Death Knight (able to cast fireball once per tac battle) - if not 'employed' by a necromancer then normally found in it's keep

mindflayer (high mental powers: charm, fear, & magic upon higher lvls)

Soulmage (each additional unit? in the soulmage's army acts as an additional power node as far as spells are conserned, each unit affected loses 20%? hit points per spell cast or different amounts depending on spell lvl)

animated armor (mentioned above could be another neat militia unit for cities & outposts)

ifreet

d'jin (sorry for my spelling today & also sorry if I'm duplicating anyones mentions)

I dream of _______ (hint: had 'her' own tv show, says 'yes master' alot

imp (Can cast 3 random low lvl spells, can cast retreat self)

shaman - common magic user found amongst many neutral factions

pixxie - trouble-mischivious, normally found in wooded areas

fairy - See Fire Giant

unicorn - Special kind of horse that can be found in forests & used by some Amazonian tribes & many other all female nations due to the horns 'special magic'

carrion crawler - dangerous *ss big catapillar, stunning victum upon succesful hit

invisible stalker - I think I've seen this movie

Yunti - Those half-snake/half-man creatures, they eat humaniods, have shamans/clerics & such, dwell mostly underground

There's also them 4 armed chicks that are immune to non-magical weapons, normally can be found in a local brothel (I remember some creatures are immune to magic attacks & are susceptible to basic weapons only, but don't recall the name)

harpy 

-------------------------------------------------------------------------- I'll be updating/adding

Summon Wall (?)

LOL @ the smurf one.  Here is a silly one.

Tactical Summon - Summon Ash (Bruce Campbell Chainsaw version)

All undead units in battle receive 2X damage from Ash unit.  Ash unit receives 1/2 damage from undead units.  All female units on the screen are instant healed 25% of their health when Ash is summoned.  Ash unit is removed when combat is over.

Sweet.  Lots good stuff in this thread.

Grizzyloins - wtf indeed, my chest hurts from trying to hold in the lols.  you have a twisted mind my friend.

Hypnotic Specter:

A wispy phantom that when attacks hypnotizes its opponent.

mechanic: Reduces Initiative of the creature it attacks for the next round.

Defiler:

A construct of death. This monstrosity siphons the life of its comrades to fuel his evil magics.

mechanic: Has access to every tactical death spell, but instead of using mana to fuel his spell the mana cost is life drained evenly from all other units on his side equal to the amount of the spell. IE... spell cost 120 mana and there is 4 other units on his side, 30 life would be drained from each unit to cast this spell. If the division ends up in with a fraction then round up to nearest whole number.

Seraphim Guardian:

A incorproral divine castodian that refusse to comment vilence on the battle field but eminates powerful protective guidence to her chosen ally.

mechanic: Upon summon or start of battle, she choose an ally. When that ally is attacked he gets a counter strike, and his deffense is increased inversely proportional to the distance from the seraphim. When the Seraphim is attacked it will not attack back when its life is reduced below 10 hps it will restore its target back to half life if the target is below half its life. It takes no damage from death attacks.