When I was on my server I wanted to Summon a Fireball. Since Fireballs come from Ghast I put the server difficulty on normal I typed in "/summon Fireball" it appeared for one frame and disappeared the next.

/summon command spawns in an EnderCrystal but it goes into the ground about half a block in 14w31a i stayed on top of the block. I havent gone to the end to see if the endercrystal also do that in the end but it does sink in about slab lengh when the crystal in summoned. I summon the ender cryrtal on top of a 5x5 obsidian fortress and it was hallow inside it when the bug accured