Struggling through the rares and elites in Diablo on my hyper-squishy Witch-Doctor has been complicated by the fact that these mobs can spawn with any combination of lethal abilities. After some search, I found a very useful post on D3DB.com, which clearly details all the abilities that rare and elite mobs may possess. This is invaluable information, so I thought I should share it as well. Thanks for putting it together Everamilli!
Here are the abilities that any given unique mob will have. They often come in groups of three and some of them can be rather tricky:
Nightmarish – Will drop a fear bomb and will send you and your companions running in fear for ~3 seconds.
Molten – Will leave a path of lava wherever they go; it will cause a small amount of damage continuously while you stand in the fire. Can cause a floor full of hurt if in a confined area. Also, upon death, the mob will explode causing a large amount of AoE damage.
Teleport – Will randomly teleport to an area in close vicinity. Try to keep them stunned. If they do teleport, best to use your gap closers here.
Vortex – Will suck you in toward them at random times. If you are a ranged, use knock backs and speed boosts naow.
Mortar – Will run from you and fire a barrage of ~5 or 6 fireballs in an arcing path. They can be avoided rather easily if you don’t get tunnel vision.
Knockback – Will knock you back randomly. Nothing you can really do but use a gap closer here as well.
Plagued – Will drop pools of green poison. Just kite them out of the pools and don’t stand in them.
Frozen – Will spawn up to five frozen orbs that will explode after a few seconds, causing damage to anyone in close proximity and freezing you in place for ~3 seconds.
Waller – Creates walls that can often trap you and your companion if you don’t move.
Jailer – Similar to Freezer (see above), will conjure a red circle that will root you for ~2 seconds.
Electric - Will continuously emit electrical pulses that crawl along the ground in 360 degrees.
Fast – Increased movement and attack speed. You can’t really outrun them, better to use knockback / stun.
Illusionist – Create copies of themselves with about 20% of their original HP. Really dangerous if they are in pack, as if they all use illusion at the same time, you’ll get circled by the copy and unable to escape.
Invulnerable Minions – Must kill the champion mob, minions take no damage (hence the invulnerable). Once the champion mob is killed, the minions die instantly. First Seen in Hell mode.
Arcane Enchanted – Mobs will spawn an orb that shoots out an arcane laser that will spin in one full circle before going away.
Shielding – Casts a shield around one of your enemies.
Vampiric – Every landed hit (including projectiles) will heal the mob.
Fire Chains – Will cause the champion mobs to connect via a fiery chain that will damage you if you cross it.
Health Link – When pack of mobs is near each other they share incoming damage from the party and every mob take only a % of total damage done. If mobs are away health link is broken. Can be seen as a dark red chain between mobs. Animation in flashing every few seconds only.
Avenger – When one of the mobs die, others in the pack become stronger. Last mob in the pack is going to enrage (becomes much bigger and gain red colors in his texture). Enraged mob is much faster and stronger.
Desecrator – Mobs create fire circle under party members that starts to burn you with fire damage 1 second after its creation.
Horde – The mob summons additional minions.
Missile Dampening – Slows all projectiles and spells around the mob.
Suicide Bomber – Will kamikaze you and explode, causing massive amounts of damage, while dropping no loot.