Alchemical Hydra
A 95 Slayer boss at Mount Karuulm. It cycles through forms, uses ranged and magic, and needs to be dragged through chemical vents.
How the fight works
The Hydra attacks with ranged and magic and changes form as its health drops. Its defences partly absorb your hits until it has been drawn through the right chemical vent, so lure it across a vent before you dump damage. Stay out of the poison and fire it leaves on the floor.
Drops
Brimstone ring pieces
The three ring pieces rotate on BLST: each new piece you receive is the next one in the order eye, fang, heart, so you never get the same piece twice in a row.
| Item | Quantity | Chance |
|---|---|---|
 Jar of Chemicals Unique | 1 | 1/1,3440.0744% |
 Icon segment Unique | 1 | 1/1,2730.0786% |
 Ikkle Hydra UniquePet, rolled separately | 1 | 1/1,0010.0999% |
 Hydra's claw Unique | 1 | 1/6730.149% |
 Hydra leather Unique | 1 | 1/4500.222% |
 Hydra tail Unique | 1 | 1/4490.223% |
 Hydra bones | 2 | Always |
 Chaos rune | 150-300 | 1/5.1919.3% |
 Death rune | 150-300 | 1/21.64.64% |
 Blood rune | 150-300 | 1/21.64.64% |
 Astral rune | 150-300 | 1/21.64.64% |
 Dragonstone bolts (e) | 100-120 | 1/21.64.64% |
 Onyx bolts (e) | 35-50 | 1/21.64.64% |
 Coins | 50,000-90,000 | 1/263.84% |
 Crystal key (noted) | 1-4 | 1/263.84% |
 Shark | 2-4 | 1/263.84% |
 Ranging potion(3) | 2 | 1/263.84% |
 Super restore(3) | 3-4 | 1/263.84% |
 Alchemical hydra heads | 1 | 1/263.84% |
 Dragon bones (noted) | 30-50 | 1/263.84% |
 Mystic fire staff | 1 | 1/43.92.28% |
 Mystic water staff | 1 | 1/43.92.28% |
 Battlestaff (noted) | 8-12 | 1/43.92.28% |
 Black d'hide body | 1 | 1/43.92.28% |
 Dragon longsword | 1 | 1/43.92.28% |
 Dragon med helm | 1 | 1/43.92.28% |
 Rune platebody | 1 | 1/43.92.28% |
 Dragon battleaxe | 1 | 1/43.92.28% |
 Rune platelegs | 1 | 1/43.92.28% |
 Rune plateskirt | 1 | 1/43.92.28% |
 Mystic robe top (light) | 1 | 1/43.92.28% |
 Mystic robe bottom (light) | 1 | 1/43.92.28% |
 Clue reward scroll (hard) | 1 | 1/1070.939% |
 Clue reward scroll (elite) | 1 | 1/1580.633% |
 Hydra's eye | 1 | 1/5020.199% |
 Hydra's fang | 1 | 1/5020.199% |
 Hydra's heart | 1 | 1/5020.199% |
 Dragon knife | 500-1,000 | 1/5020.199% |
 Dragon thrownaxe | 500-1,000 | 1/5020.199% |
Chance per kill for a player with no drop bonus. See Game modes and XP rates for how bonuses change these numbers.