Necrotic Ooze + Wizard Class + Barrenton Medic + Archivist

Necrotic Ooze

Wizard Class

Barrenton Medic

Archivist

How it works

1. Activate Necrotic Ooze using Archivist's ability by tapping it, causing you to draw a card.
2. Wizard Class triggers, putting a +1/+1 counter on Necrotic Ooze.
3. Activate Necrotic Ooze using Barrenton Medic's second ability by putting a -1/-1 counter on it, untapping it.
4. Repeat.