Explosive Turtle (5e Creature)
From D&D Wiki
Small construct, unaligned
Saving Throws Con +5
Glow. The turtle glows, offering dim light in a 10 ft. radius centered on it.
Metallic Bite. Melee Weapon Attack: +3 to hit, reach 5 ft, one target. Hit: 5 (1d8 + 1) piercing damage.
Sacrificial Explosion. The turtle explodes, causing all creatures in a 10 ft. radius to make a DC 14 Dexterity saving throw to avoid taking 16 (3d10) fire damage, or half as much on a successful save. Upon using this action, the turtle dies.
Explosive Impulse. When the turtle sees an intruder, it uses its Sacrificial Explosion action. If it dies from anything except Sacrificial Explosion, it uses its Sacrificial Explosion action before dying.
Explosive turtles aren't living things, they are just machines made to explode and kill intruders. Their inventor said: "Nothing is better than an explosion." Then he exploded to pieces.