Horde (HD 8; AC 0)

Dominik Mayer
this started as a Joesky tax, then i realized it was 100x more interesting than the article it was attached to

Never run zombies as individual monsters ever again.

Zombie Horde
HD 8; Morale 12
There are as many zombies as the horde has HP. Attacks automatically dispatch as many zombies as they hit.
Horde "Tactics": The horde doesn't attack conventionally; instead, take 1 damage for each zombie within arms reach at end of round (no save), and 1 damage for each zombie you pass through the reach of while moving (save for half, round down).
Characters who look, sound, and/or smell like zombies (at least 2 of those) take no damage.
Only Slowed Them Down: Each round, half of the zombies you dispatched get back up and rejoin the horde, so long as their bodies are still intact.
They Just Keep Coming: Each round, 1d6 new zombies shamble around the nearest corner. This continues until the source is discovered and neutralized or the horde stops chasing you. (you're probably fine if you walk around the corner; they're very dumb)

Other monsters to horde-ify: goblins; orcs; swarms of bees; sharks; town guardsmen; plant monsters; velociraptors