Large Monstrosity, unaligned
Armor Class 16 (natural armor)
Hit Points 127 (15d10+45)
Speed swim +30, walk +40
Challenge 5
Saving Throws dex +7, wis +3
Skills perception +3
Damage Resistances poison
Senses blindsight 10ft., passive Perception 13
Languages -
Reactive Heads. The three-headed cobra gets two extra reactions that can be used only for opportunity attacks.
Three-Headed. The cobra has advantage on Wisdom (Perception) checks and on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious.
Wakeful. While the three-headed cobra sleeps, at least one of its heads is awake.
Multiattack. The three-headed cobra makes three bite attacks.
Bite. Melee Weapon Attack: +7 to hit, reach 15 ft., one target. Hit: 7 (1d6 + 4) piercing damage and the target must make a DC 15 Constitution saving throw, taking 7 (2d6) poison damage on a failed save, or half as much damage on a successful one.
Source: Creature Codex · OGL/Open