Thothuxin, the Witness

Flying, Hexproof
Whenever you cast an instant or sorcery spell, Thothuxin, the Witness deals 4 damage to target creature or planeswalker an opponent controls.
{6}{u}{r}: Create a token copy of Thothuxin, the Witness except it isn't legendary. This ability
costs {1} less for each creature named Thothuxin,
the Witness you control.