Necrotic Ooze + Devoted Druid + Grim Poppet

Necrotic Ooze

Devoted Druid

Grim Poppet

How it works

1. Activate Necrotic Ooze using Devoted Druid's first ability by tapping it, adding .
2. Activate Necrotic Ooze using Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
3. Activate Necrotic Ooze using Grim Poppet's ability by removing a -1/-1 counter from it, targeting any other creature.
4. Holding priority, activate Necrotic Ooze using Devoted Druid's first ability by tapping it, adding .
5. Repeat from step 2.