Hydras can be assigned as a slayer task at level 95 slayer by Konar quo Maten. There are two different types of hydras: normal hydras and the Alchemical Hydra, both of which are only found in the Karuulm Slayer Dungeon. The dungeon requires the player to wear Boots of stone, Boots of brimstone or Granite boots to protect themselves from the extreme heat of the dungeon floor, unless the player has completed the Elite Kourend & Kebos Diary. Hydras have a Superior slayer monster variant, the level 309 Colossal Hydra.
Hydras start off with a random combat style between ranged and magic at the start of the battle, switching after three attacks, regardless if they hit or not. If the hydra still persists after roughly 30 seconds into a fight, it will spit poison at three random tiles (one at the player's location, two elsewhere), dealing 4 poison damage every two ticks (or 1 to 2 damage if the player has poison immunity) when the player is standing on one. The initial splat has a 3x3 AoE. It is recommended to start by activating the protection prayer that protects the player against the attack style they have lowest defense towards, typically magic if wearing melee armour or ranged if wearing ranged armour, then switching to the other protection prayer if the hydra starts with an attack of the other style.
||Bigger and Badder
||Increase the risk against certain slayer monsters with the chance of a superior version spawning whilst on a slayer task.