Activate Scaretiller by tapping it, targeting Cacophodon.
Scaretiller triggers, returning Maestros Theater from your graveyard to the battlefield tapped.
Maestros Theater enters the battlefield, triggering itself and Roaring Earth.
Resolve the Roaring Earth trigger, putting a +1/+1 counter on Cacophodon.
Resolve the Maestros Theater trigger, causing you to sacrifice it and search your library for a basic Mountain, Island or Swamp and put it onto the battlefield tapped.
If you put a land onto the battlefield this way, Roaring Earth triggers, putting a +1/+1 counter on a creature you control.
Resolve the Scaretiller ability from step 1, dealing 1 damage to Cacophodon.
Cacophodon triggers, untapping Scaretiller.
Repeat.
Results
Infinite +1/+1 counters on Cacophodon.
Infinite landfall triggers.
Put all basic Islands, Swamps, and Mountains from your library onto the battlefield.