Cryptic Trilobite has any +1/+1 counters, activate
Cryptic Trilobite's first activated ability until it has no +1/+1 counters, adding ({C} magic symbol) ({C} magic symbol) that can only be spent to activate abilities each time.
Activate
Phyrexian Altar by sacrificing
Cryptic Trilobite, adding ({1} magic symbol) .
Cryptic Trilobite's undying ability from
Mikaeus triggers, returning
Cryptic Trilobite from your graveyard to the battlefield with a +1/+1 counter on it.
Repeat.
Results
Infinite colored mana.
Infinite colorless mana that can only be used for activated abilities.