The Brotherhood of Mutants

Whenever a Mutant enters the battlefield under
your control, deal 1 damage to any target.
{5}: Exile target Mutant you don't control, then
return it to the battlefield under your control
until end of turn. It gains haste until end of turn.
Activate this ability as a sorcery, and only once
per turn.
"Earth is now the dominion of mutantkind!"