The Thing + Agatha's Soul Cauldron + Sage of Hours + Elvish Fury

The Thing

Agatha's Soul Cauldron

Sage of Hours

Elvish Fury

How it works

1. Cast Elvish Fury with buyback by paying 4, returning it to your hand.
2. At the beginning of your combat phase, The Thing's first ability triggers, putting four +1/+1 counters on it.
3. Declare The Thing as an attacker. Its second ability triggers, causing you to pay to double the number of +1/+1 counters on it.
4. Activate The Thing using Sage of Hours' ability by removing all +1/+1 counters from it, causing you to take an extra turn after this one.
5. Repeat each turn.