Hell's Caretaker + Body Double + Anger

Hell's Caretaker

Body Double

Anger

How it works

1. During your upkeep, activate Hell's Caretaker by tapping and sacrificing it, returning Body Double from your graveyard to the battlefield as a copy of Hell's Caretaker.
2. Activate Body Double by tapping and sacrificing it, returning Hell's Caretaker from your graveyard to the battlefield.
3. Repeat.

This elegant resurrection loop relies on Hell's Caretaker trading itself away during your upkeep to pull Body Double from the graveyard, which enters as a fresh copy of Hell's Caretaker. Because this new copy isn't constrained by "summoning sickness" the moment it enters, you can immediately tap and sacrifice it to pull the original Hell's Caretaker back out, setting up an endless cycle of sacrifices and returns. Meanwhile, having Anger in your graveyard (assuming you control a Mountain) ensures that any creatures entering the battlefield as a result of these triggers immediately gain haste, turning your endless loop into a terrifying engine for all manner of sacrifice, entry, and death triggers.