Plesiosaurus

Large beast, unaligned

Armor Class 13 (natural armor)
Hit Points 68 (8d10 + 24)
Speed 20 ft., swim 40 ft.

STR	DEX	CON	INT	WIS	CHA
18 (+4)	15 (+2)	16 (+3)	2 (-4)	12 (+1)	5 (-3)

Saving Throws 
Skills Perception +3, Stealth +4
Damage Resistances 
Damage Immunities 
Condition Immunities 
Senses passive Perception 13
Languages --
Challenge 2 (450 XP)

Hold Breath. The plesiosaurus can hold its breath for 1 hour.

Actions

Bite. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 14 (3d6 + 4) piercing damage.