n tiny animal aquatic 

Perception +8; darkvision, wavesense (imprecise) 30 feet

Skills Athletics +4, Stealth +5, Survival +4

Str +1 Dex +3 Con +2 Int -5 Wis +2 Cha +0

AC  15; Fort +4, Ref +7, Will +4

HP 7

Curl Up [R] Trigger The trilobite takes damage; Effect The trilobite gains a +2 circumstance bonus to AC until the start of its next turn.

Speed swim 25 feet

Melee [>] gnathobase +7 (agile, finesse), Damage 1d4+1 slashing

Quick Escape [>>] The trilobite swims up to double its.

Bestiary 3, page 275.