Arthropod Egg

Some civ servers add the ability to obtain mob spawn eggs by killing mobs with a sword enchanted with Bane of Arthropods (an otherwise generally useless enchantment).

Mechanics
Killing a mob with a weapon that has the Bane of Arthropods enchantment has a chance to drop a spawn egg item for the slain mob type. Each level of "Bane of Arthropods increases the drop rate by 3%. The drop rate increases by 2% for every Looting enchantment level. A monster that drops a spawn egg will not drop any other loot.

It is possible to get the spawn eggs of all passive mobs except for Snow and Iron Golems.