This mod lets you stack, throw, and dispense Spawn Eggs. It would let people make some very interesting custom maps.

Server download here. (any players will need the client download for the eggs to work.

Note: this mod is probably incompatible with just about everything.

If you use it in multiplayer on an unmodded server it throws the eggs, but will only spawn mobs where it would normally spawn them.

Changelog:

Please give feedback or examples of how you use it, or if this is compatible with any mods.