The Ender Dragon

Flying, Menace
The Ender Dragon has Indestructible as long as
you control an End Crystal
When The Ender Dragon enters the battlefield,
Create 10 0/1 End Crystal Artifact Creature
Tokens with "Defender" "{t}{2}Sacrifice this
creature, Draw a card" and "When this creature
leaves the battlefield, it deals 4 damage to target
creature"