({1} magic symbol) if Cryptic Trilobite does not have a +1/+1 counter on it available.
Steps
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 step 1 until Cryptic Trilobite does not have any +1/+1 counters on it.
Activate Skullclamp's equip ability by paying ({1} magic symbol) , attaching it to Cryptic Trilobite.
Cryptic Trilobite dies as a state-based action due to having zero toughness, triggering its undying ability and Skullclamp.
Resolve the Cryptic Trilobite trigger, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Resolve the Skullclamp trigger, causing you to draw two cards.
Repeat.
Results
Infinite card draw.
Infinite draw triggers.
Near-infinite colorless mana that can only be spent to activate abilities.