You have had three nontoken creatures enter the battlefield under your control this turn.
Mana Needed
({1} magic symbol) available.
Steps
Activate
Tromell by paying ({1} magic symbol) and tapping it, causing you to put at least three +1/+1 counters on
Cryptic Trilobite.
Activate
Cryptic Trilobite twice by removing two +1/+1 counters from it, adding ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) that can only be spent to activate abilities.
Activate
Sword of the Paruns by paying ({3} magic symbol) , untapping
Tromell.
Repeat.
Results
Infinite colorless mana that can only be spent to activate abilities.