Mikaeus, the Unhallowed + Phyrexian Altar + Furystoke Giant

Mikaeus, the Unhallowed

Phyrexian Altar

Furystoke Giant

How it works

1. Activate Phyrexian Altar by sacrificing Furystoke Giant.
2. When Furystoke Giant dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Activate Phyrexian Altar by sacrificing Furystoke Giant.
4. When Furystoke Giant dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
5. Repeat.