Advanced Octopin

Penetrating Vision. An octopin can see through up to 2 feet of wood or earth, six inches of stone or metal, or one inch of lead as if it were not there. It is immune to the visual components of figments or illusion spells, and can see invisible creatures. It still requires line of effect in order to use its slowing gaze on an opponent.

Multiattack. The Octopin can use its slowing gaze and makes two claw attacks. If the octopin hits with both tentacle claw attacks, it latches onto the opponent's body and tears the flesh. The target takes an additional 2d8 + 7 points of bludgeoning damage

Claw. Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 11 (3d6 + 6) slashing damage. 

Slowing Gaze. The octopin targets one creature it can see within 30 feet of it. If the target can see the octopin, the target must succeed on a DC 16 Wisdom saving throw against this magic or be affected by the gaze for 1 minute.

An affected target's speed is halved, it takes a −2 penalty to AC and Dexterity saving throws, and it can't use reactions. On its turn, it can use either an action or a bonus action, not both. Regardless of the creature's abilities or magic items, it can't make more than one melee or ranged attack during its turn.

If the creature attempts to cast a spell with a casting time of 1 action, roll a d20. On an 11 or higher, the spell doesn't take effect until the creature's next turn, and the creature must use its action on that turn to complete the spell. If it can't, the spell is wasted.

A creature affected by this spell makes another Wisdom saving throw at the end of each of its turns. On a successful save, the effect ends for it.