Cryptic Trilobite has at least two +1/+1 counters on it.
({1} magic symbol) available.
Steps
Activate Marath by paying ({1} magic symbol) and removing a +1/+1 counter from it, putting two +1/+1 counters on Marath.
Activate Marath by paying ({1} magic symbol) and removing a +1/+1 counter from it, putting two +1/+1 counters on Cryptic Trilobite.
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.
Once Cryptic Trilobite has infinite +1/+1 counters, you may remove them for infinite mana, then repeat step 1 to get infinite +1/+1 counters on Marath, which can then be used for Marath's other modes.
Results
Infinite +1/+1 counters.
Infinite colorless mana that can only be spent to activate abilities.