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.
Beware of towns afflicted with Time Cancer.
For every second you progress through time, an infected town goes back 48 hours. Old buildings slowly become new, then incomplete, and finally just a frame and foundation, giant old trees turn to saplings, birds hatch into eggs.
one must not linger in a chrono-cancerous village for too long, before you know it you'll be a fetus. Tme cancer in unstoppable, no cure or treatment is knwn, it eats through the past until the inhabitants of a village turn into primordial protein ooze