Bipedal Mudfighter

Born of Tainted Mud. The Mudfighter can only be summoned by the class feature Manifest Mudfighter from the Soul of Tainted Mud Sorcerer.

Binding Expiration.  When this creature is reduced to 0 hitpoints, it bursts into a spray of Tainted Mud, forcing a hostile creature within 10 feet to make a DEX saving throw equal to the summoning Sorcerer's Spell Save DC. On a failed save, the target creature is considered Restrained until its next turn.

Adapt Weapon. Each Bipedal Mudfighter can wield a single weapon upon being summoned. Any weapon they wield is considered improvised, and they do not gain any benefits from attunement or suffer any curses a weapon would normally entail.

Tainted Slap. Melee Weapon Attack: +(Summoner's CHR + Proficiency) to hit, reach 5 ft., 1 target. Hit: 8 (2d4 + 2) [Bludgeoning] damage. 

Restraining Sentinel. If a Bipedal Mudfighter is not wielding a weapon or using its limbs, when a hostile creature exits its combat range, the Bipedal Mudfighter can attempt to grapple it.

Strength saving throw equal to the summoning Sorcerer's Spell Save DC

on a failed save, the hostile creature is grappled until the end of its turn, at which point it can repeat the saving throw. If the Mudfighter is damaged before this save, the grappled creature makes the save at advantage. On a successful save, the creature is unaffected.