Stone Camouflage. The grick has advantage on Dexterity (Stealth) checks made to hide in rocky terrain.

Acidic Blood. When the grick is struck by a weapon attack, acidic blood sprays violently. All creatures within 5 ft of the grick must succeed on a DC14 Dexterity Saving Throw or take 4 (2d4) acid damage. 

Multiattack. The grick makes one attack with its tentacles. If that attack hits, the grick can make one beak attack against the same target.

Tentacles. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 9 (2d6 + 2) slashing damage, +4 (2d4) acid damage

Beak. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) piercing damage.