An incarnation of Laserbeak, and condor/cyborgs for the Cosmic Era
Do not meddle in the affairs of wizards... -- Gildor, via J R R Tolkien
The first sign of the Army of the Lost are the legs. Blown off legs, hopping along wearing their military boots. And not long afterwards, the rest of the Army arrives, and the horizon from left to right is filled with the decomposing bodies, many of which carry weapons. Unless you can outrun them or fortify your position, you will soon be joining this army of the Undead.
A PC Conjurer or summoner, basically any mage whose sole purpose in life is summoning creatures to aid in battles and various situations, is cursed with a hex, and needs to find a way to undo the curse...before he goes mad, or his fellow PCs throw him out of the party, or worse.
Everything he/she summons, never goes away. So you'll have to figure out what the heck to do with that dire bear or fire elemental once it's done fighting the orcs for you. Eventually a caravan of bizarre creatures either annoyingly ends up following the summoner around, or they go off to cause mayhem elsewhere. Bad news for the poor spell-caster regardless.