Activate Gilder Bairn by paying ({2} magic symbol) ({GU} magic symbol) and untapping it, doubling each counter 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 you have infinite +1/+1 counters on Cryptic Trilobite, you may instead double the counters on any other permanent(s).
Results
Infinite +1/+1 counters on Cryptic Trilobite.
Infinite colorless mana that can only be spent to activate abilities.