Cradle Clearcutter + Umbral Mantle

Cradle Clearcutter
Umbral Mantle

Requires
All permanents on the battlefield. Umbral Mantle attached to Cradle Clearcutter. Cradle Clearcutter does not have summoning sickness. Cradle Clearcutter has a power of three or greater.
Steps
  1. Activate Cradle Clearcutter by tapping it, adding at least ggg
  2. Activate Cradle Clearcutter by paying 3 and untapping it, giving it +2/+2 until end of turn
  3. Repeat
Results
Infinite green mana. Infinitely large Cradle Clearcutter until end of turn.