Attor, The Decayed Leviathan

{t}, Tap three untapped creatures you control:
Add {c}{c}{c} to your mana pool.
{t}, Sacrifice Attor, The Decayed Leviathan, and seven creatures you control: Create a 10/10 Leviathan Skeleton creature token with flying
and haste.
Attor's days of being the ruler of the sea have ended. Now he serves as a meeting place for cultists in the drownyard.