Bukkit/Bukkit — comment on commit 4e92f59d4cf85173b838cb7dd8a710859d23995c
File:  line 0
By Jadedwolf:

That spawns the egg with "entity.ender.crystal"
But does not work when right clicked as it does with the vanilla server.
Thus they can be spawned in bukkit but do nothing, unlike vanilla where they actually work.