The Retcher is a creeper variant that doesn't directly replace the creeper but spawns alongside it in jungle and swamp biomes. However the Retcher doesn't blow up like the creeper destroying blocks, it blows up when it come in close quarters with the player and gives nausea and poison for 12 seconds, it also leaves behind a poisonous area of effect similar to a lingering potion of poison. You can use a water bottle on it to get a potion of poison and to reduce the negative effects by 50%. Killing it before it explodes gives you gunpowder and green dye with a 10% chance of also giving lime dye