Ridgescale Tusker enters the battlefield, putting a +1/+1 counter on each creature you control.
Activate Crystalline Crawler's first ability by removing a +1/+1 counter from it, adding ({1} magic symbol) .
Activate Cryptic Trilobite's first ability by removing a +1/+1 counter from it, adding ({C} magic symbol) ({C} magic symbol) that can only be spent to activate abilities.
Repeat.
Results
Infinite +1/+1 counters on all creatures you control except Ridgescale Tusker, Crystalline Crawler and Cryptic Trilobite.