Rupture (5e Creature)
From D&D Wiki
medium aberration, chaotic evil
Death Burst. When the rupture dies, it explodes in a burst of acid. Each creature within 5 feet of it must make a DC 10 Dexterity saving throw, taking 7 (2d6) acid damage or half as much on a successful one. On a failed save, the creature also takes 1 acid damage at the start of every turn for 1 minute.
Headbutt. Melee Weapon Attack: +2 to hit, reach 5 ft., one target. Hit: 7 (2d6) bludgeoning damage.
Explode. The rupture moves up to its speed and dies, activating the Death Burst.
Ruptures, the only purposefully suicidal creature on the face of the planet. That's what they're designed to do, run right at their enemies and detonate. And they're very good at that. They are normally found in areas of intense chaos, like Limbo, but even though they have almost no intelligence to speak of, they do alright in these uncontrollable regions.