Chaos Elemental is a dark cloud with six tentacles. The Chaos Elemental is immune to venom —any items that are able to inflict venom will inflict regular poison instead. It has a combat level of 305 and is a bit hard to kill. Chaos Elemental can also drain prayer "Soulsplit".
You can find Chaos Elemental in two places, such as Sponsor Zone, also known as Ownercape or Ownercape Zone (you must be a sponsor) and by using the Boss Teleport System.
The best way to kill this boss is by using prayer "SoulSplit" (Level 92 prayer recommended) Since this boss drain prayer "Soulspit", it's best to bring a few prayer potions and some food (Rocktail or Shark). You're also going to need a fast hitting weapon, such as an Ice katana, soulflare,soulflare (u) or a minigun. You're also going to need armor, such as Elemental, Shadow Torva, America Torva, or America Pernix.