Creeper

Vulnerability to Fire. In addition to being vulnerable to fire damage, a Creeper that is dealt at least 3 points of fire damage in a single attack starts detonating, as if it had used its explode ability. If this occurs, it does not hiss, meaning that creatures within range of it are unaware of the event and cannot make a Dexterity saving throw to move out of the way. However, creatures within range of the detonating Creeper can still make a Constitution save to halve the damage.

Explodable Body. The body of a Creeper is filled with gunpowder, which remains dangerous after its death. A Creeper who did not attempt to explode and who was slain in a way that did not involve fire damage can be cut open to gather the explosive. This yields gunpowder with a worth of 675 gp per batch.

The corpse of a Creeper can also be set off by dealing at least 3 points of fire damage to it in a single attack, causing it to explode as if the Creeper was still alive.

Natural Camouflage. When in grassland or hill biomes, the Creeper has a +4 racial bonus on Dexterity (Stealth) checks instead of +2.

Lightning Absorption. Whenever the Creeper is subjected to lightning damage, it takes no damage and regains a number of hit points equal to the lightning damage dealt. In addition, if the Creeper absorbs at least 3 Lightning damage, it becomes charged, and a sparkling, blue aura surrounds its body. When charged, the Creeper is immune to invisibility, and it's explode attack deals double damage, but is still halved on a successful Constitution save.

Slam. Melee Weapon Attack: +2 to hit, range 5 ft., one target. Hit: (1d3) bludgeoning damage.

Explode. As an action, a Creeper can blow itself up, but this process is not easy and is usually a last resort attack. First, a Creeper hisses, automatically alerting all creatures that can hear it to its presence. Second, every creature within 15 feet of the Creeper can make a DC 17 Dexterity save to move 15 feet away from the Creeper. The Creeper then explodes, dealing (2d12) fire and bludgeoning damage to all creatures within 15 feet. Objects within 15 feet instead take (4d12) bludgeoning and fire damage. A DC 12 Constitution save halves this damage. The Creeper is immediately reduced to 0 hp after using this ability.