Crimson Centipede

Pliable. The Crimson Centipede may enter a space that seems too small for it such as small cracks and ear canals.

Death Burst. When the Centipede dies, it explodes in a burst of blood. Each creature within 5 feet of it must make a DC 15 Dexterity saving throw, taking 7 (2d6) fire damage on a failed save, or half as much on a success. Any creature affected by Vein Splice instantly fails the save.

Aggressive. As a bonus action, the creature can move up to its speed toward a hostile creature it can see.

Ambusher. The creature has advantage on attack rolls against any creature it has surprised.

Multiattack. The Centipede makes either two pincer attacks, a pincer and an Ear Crawl attempt, or an Ear Crawl attempt followed by Vein Splice.

Pincer. Melee Weapon Attack: +6 to hit, reach 5 ft., single target. Hit:  2 (1d4 + 4) [Piercing] damage. The centipede may use its pincers while inside a target.

Ear Crawl. (Recharge 3-6) The Crimson Centipede launches itself at a target creature of large or smaller size attempting to enter their ear and forcing the target creature to make a DC 12 Dexterity saving throw. Upon failure, the Crimson Centipede is now inside the creature's ear or another orifice. The affected creature may make a DC 16 Dexterity saving throw at the start of their turn to attempt to remove the Crimson Centipede, upon success the creature grapples the target and may pull them out.

Vein Splice. So long as the Crimson Centipede has successfully entered a target creature's orifice, it may connect its veins via stinger located between the centipede's pincers to the affected creature. At the start of the assailant creature's next turn, it takes 8 (1d4 + 6) fire damage as the Centipede's blood begins coursing through their veins.

Final Destination. As a reaction to being hit or grappled by another creature, the Crimson Centipede may use its reaction to self destruct.