Giant Wither boss bound to destroy us all!

OMG Witherzilla!!!!, It's giant, it's invulnerable it's unable to move, and it's not aggressive. An ender dragon would be more like the ender dragonfly compared to this guy, a block not even be one pixel, and I would be like the size of a flea. If you want that huge wither boss, do /summon WitherBoss ~ ~ ~

{Invul:30000,CustomName:Dinnerbone}

. This works simply because since the Wither is named Dinnerbone, its growth is reversed and instead of turning it into a regular sized wither, starts out as a humungous invulnerable wither at full health. Credit to SimplySarc who discovered the glitch.