Intimidating Presence. Can use your action to frighten someone with your menacing presence. When you do so, choose one creature that you can see within 30 feet of you. If the creature can see or hear you, it must succeed on a Wisdom saving throw (DC equal to 13) or be frightened of you until the end of your next turn. This effect ends if the creature ends its turn out o f line of sight or more than 60 feet away from you. If the creature succeeds on its saving throw, you can't use this feature on that creature again for 24 hours.

Underground Hunters. Corpsers use their powerful claws to tunnel through the earth when they hunt. Heedless of obstruction, they uproot trees, cause landslides in loose slopes, and leave sinkholes behind them. When vibrations in the soil and rock alert a corpse to movement, it shoots to the surface, its jaws spread wide as it attacks.

Single Claw. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 12 (2d8 +3) piercing damage. (Can´t be used undrground).

Miltiattack. Corpser makes four single claws attacks. Scratch. Casting Time: 1 action, Range: 5 feet, Duration: 2 rounds. Use their powerful claws to tunnel through the earth at least 15 feet. While its underground can´t receive damage from anywhere.

Underground Stinger. Melee Weapon Attack: +6 to hit, reach 10ft., one creature. Hit: 11 (1d12 +5) piercing damage. The target must make a DC 15 Dexterity saving throw, taking half as much damage on a successful one. (Only can be used underground).

Deadly Ascends. Use this action to arise on its feet in a space that contains one or more other creatures. Each of those creatures must succeed on a DC 15 Dexterity saving throw (target' s choice) or be knocked prone and take (1d8 +5) bludgeoning damage. On a successful save, the creature takes only half the damage , isn't knocked prone, and is pushed 5 feet out of the Corpser´s space into an unoccupied space of the creature's choice. If no unoccupied space is with in range, the creature instead falls prone in the Corpser's space. (Only can be used underground).

The Hare And The Tortoise. Their legs are immune to common atacks; Bludgeoning, Piercing, Slashing.

Slow But Safe. The Cropser adopt a defensive form reducing his own movement speed to 5fts. and moving towards an enemy until being at the attack range, during Slow But Safe acquires damage immunitis to non magical piercing and slashing damage  to all attacks that  come from opposite his, also becomes vulnerable to all attacks that come from behind, adittionaly get blinded  condition.