Glen Elendra Archmage + Yahenni, Undying Partisan + Hardened Academic

Glen Elendra Archmage

Yahenni, Undying Partisan

Hardened Academic

How it works

1. Activate Yahenni by sacrificing Glen Elendra Archmage.
2. When Glen Elendra Archmage dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Hardened Academic triggers, putting a +1/+1 counter on Glen Elendra Archmage.
4. Resolve the Yahenni ability.
5. Repeat.