Unstable Gateway

{t}: Add {c} to your mana pool.
{2}, {t}: Choose target creature you control, then flip a coin. If heads, exile that creature, then return that card to the battlefield under your control. If tails, exile that creature.
{4}, {t}, Sacrifice Unstable Gateway: Exile target creature you control, then return that card to the battlefield under your control at the beginning of the next end step.