Plesiosaurus Large / beast / Unaligned / CR 2 Armor Class13 Hit Points68 (8d10 + 24) Speed20 ft, swim 40 ft Challenge2 Proficiency- STR18+4DEX15+2CON16+3INT2-4WIS12+1CHA5-3 TraitsHold BreathThe monster can hold its breath for 1 hour. ActionsBiteAction. .