Adaption. SCP-682 can adapt to anything after getting hit by an attack. As a reaction after getting hit by a damage type SCP-682 can adapt gaining resistance for 1d4 rounds after which it gains immunity for up to 1 week. It can have up to three different immunities at a time besides poison. If SCP-682 tries to get a fourth immunity the oldest immunity goes away. SCP-682 can spend 1 immunity to escape magical confinement.
Keen Senses. SCP-682 has advantage on Wisdom (Perception) checks that rely on sight, hearing, or smell.
Regeneration. SCP-682 regains 15 hit points at the start of its turn if it has at least 1 hit point.
Magic Resistance. SCP-682 has advantage on saving throws against spells and other magical effects.
Amphibious. SCP-682 can breathe any gas or liquid.
Magic Weapons. SCP-682 weapon attacks are treated as magical to overcome Immunities and Resistances.
Old god's heart. If it reaches 0 hp, the big reptile returns to life in 3d6 3d6 hours and regains all its hit points. This does not occur if the reptile's heart is removed. a wish spell will have no effect.
Multiattack. SCP-682 can use Frightful Presence followed by an attack. Bite. Melee Weapon Attack: +12 1d20+12 to hit, reach 5 ft., one target. Hit: 33 (6d8 + 6) 6d8+6 piercing damage. SCP-682 regains hit points equal to half of the damage dealt. Tail. Melee Weapon Attack: +12 1d20+12 to hit, reach 10 ft., one target. Hit: 28 (4d10 + 6) 4d10+6 bludgeoning damage. Claws. Melee Weapon Attack: +12 1d20+12 to hit, reach 5 ft., one target. Hit: 20 (4d6 + 6) 4d6+6 slashing damage. Frightful Presence. Each creature of the SCP-682's choice that is within 100 feet of him and aware of him must succeed on a DC 15 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to SCP-682's Frightful Presence for the next 24 hours.