Sauron, The Eye of Devastation

Flying, Indestructible, Firststrike

When this creature deals or receives damage to/from any source, you may choose to deal damage to that source equal to double the
damage dealt. If the source was a player cast spell, it deals damage to that player equal to
half the damage dealt.

Melded from Sauron, Galadriel’s Mistake
and The One Ring