OSRS Scurrius, the Rat King Boss Guide!

Deep beneath the bustling city of Varrock, a monstrous threat lurks in the sewers – Scurrius, the Rat King! Introduced as an accessible mid-level boss, Scurrius is designed to teach players core PvM mechanics like prayer switching, dodging AoE attacks, and handling adds, all while offering fantastic combat experience rates, especially when using his own drops against him.

This guide covers everything you need to know to dethrone the Rat King: location, fight mechanics, phases, strategies, loot, and instance options.

Location & Access

  • Location: Varrock Sewers (Access via manhole east of Varrock Palace). Head east from the sewer entrance.
  • Entrance: Climb through the broken bars. You can choose:
    • Public Instance: Fight a stronger Scurrius (Level 250, 1500 HP) alongside other players. Offers a +20% XP bonus.
    • Private Instance: Fight a weaker Scurrius (Level 200, 500 HP) solo or with your own group. Free to create. (Group Ironman have a shared instance option).
  • Requirements: None, but 60-90 Combat is recommended.
  • Cannons: Not allowed in the lair.

Fight Overview & Mechanics

Scurrius uses all three combat styles and introduces simple but important mechanics:

  • Weakness: Equally weak to all standard combat styles. However, he takes massively increased damage from Rat Bone Weapons (crafted from Scurrius' Spine).
  • Standard Attacks:
    • Tail Swipe (Melee): Fast, accurate melee attack. Use Protect from Melee. Max hit ~13. Only used in Phase 1 & 2.
    • Bolts of Electricity (Magic): Blue lightning projectile. Use Protect from Magic. Max hit ~14 (8 solo). Damage on impact.
    • Flying Fur (Ranged): Throws a fur ball. Use Protect from Missiles. Max hit ~13 (7 solo). Damage on impact.
  • Special Attacks:
    • Falling Bricks: Jumps, causing rubble shadows to appear. One targets your tile. Move away to avoid damage (~15-24).
    • Summon Minions: Screeches, summoning 6 Giant Rats (Level 46). They hit 0-1 through Protect from Melee (up to 4 without). Crucially, players using Rat Bone Weapons kill these rats in ONE hit with NO attack delay. Otherwise, kill them quickly using AoE or fast weapons.
    • Healing (Food Piles): Moves to one of the two Food Piles at the sides of the room to heal (~5-10 HP per tick for 5 ticks). Can still use Magic/Ranged/Falling Bricks while healing. Only occurs between 80% and 30% HP.

Fight Phases

The fight progresses through distinct phases based on Scurrius's HP:

  1. Phase 1 (100% - 80% HP):
    • Scurrius stays east, primarily using Melee Tail Swipes.
    • Occasionally uses Falling Bricks.
    • Pray Protect from Melee. Dodge bricks. DPS hard.
  2. Phase 2 (80% - 30% HP):
    • Scurrius moves to a Food Pile (randomly chosen) and begins Healing.
    • Attacks ONLY with Magic and Ranged while healing.
    • Can still use Falling Bricks and Summon Minions.
    • Strategy: Switch prayers based on incoming Magic/Ranged attacks (react on projectile launch). Kill summoned rats ASAP. Keep DPSing Scurrius to counteract healing. Dodge bricks. He stops healing after 5 heals and resumes melee if you get close, or continues Ranged/Magic if you stay at range until pushed below 30%.
  3. Phase 3 (30% - 0% HP):
    • Scurrius moves to the center of the room.
    • Attacks ONLY with Magic and Ranged at an increased speed.
    • Can still use Falling Bricks (more frequently) and Summon Minions.
    • Strategy: Focus on prayer switching between Magic/Ranged. Keep dodging bricks (they can overlap!). Kill rats quickly. Burn down his remaining health. Note: If his HP goes back above 30% (e.g., via healing from food piles if he somehow gets back to one), he reverts to Phase 2.

Post-Fight

  • Kill any remaining Giant Rats.
  • You can heal to full HP by clicking on the Food Piles (outside of combat, 10-minute cooldown).

Strategy Tips

  • Rat Bone Weapons: If you have Scurrius' Spine, craft the weapon corresponding to your best attack style (Mace - Melee, Shortbow - Ranged, Staff - Magic). The damage increase against Scurrius and the instant-kill effect on rats are massive advantages.
  • Prayer Switching: Practice reacting to the Magic (blue lightning) and Ranged (fur ball) projectile animations during Phases 2 and 3. Protect from Melee is key in Phase 1.
  • Handling Rats: If using Rat Bone Weapons, quickly tap each rat to eliminate them instantly without losing DPS ticks on Scurrius. If not, use Chinchompas, Barrage spells, or fast weapons (Darts/Knives) to clear them fast, as they bypass prayer slightly and empower Scurrius.
  • Positioning: Stay mobile to dodge Falling Bricks. In Phase 2, you can stay at range to force Magic/Ranged attacks if preferred. In Phase 3, constantly moving helps avoid overlapping brick falls.

Prioritize your best gear for your chosen style. Scurrius has low defences.

  • Melee: Dragon Scimitar/Abyssal Whip/Sarachnis Cudgel, Dragon Defender, Fighter Torso/Proselyte, Neitiznot Helm, Dragon Boots, Barrows Gloves.
  • Ranged: Magic Shortbow (i) with Rune/Amethyst Arrows, Rune Crossbow w/ Broad Bolts, Blessed/Black D'hide, Archer Helm/Coif.
  • Magic: Trident of the Seas/Swamp, Iban's Staff (U), Ahrim's/Mystic Robes, Farseer Helm.
  • General: Prayer bonus gear (Proselyte, God Vestments) helps sustain prayer. Bring Prayer potions and decent food (Lobsters/Swordfish/Sharks).

Loot Highlights

  • MVP/Solo Only:
    • Scurrius' Spine (1/33): Untradeable component used to craft Rat Bone Weapons.
    • Rune/Adamant gear, Chaos/Death/Law runes, mid-tier food/potions, coins.
  • All Participants:
    • Big Bones (Guaranteed)
    • Raw Rat Meat (Guaranteed)
    • Chance at Spine (1/33)
    • Smaller amounts of runes/food/potions.
  • Tertiary: Scurry Pet (1/3000, MVP only), Clue Scroll (Medium - 1/25, MVP only), Long/Curved Bones.

Average Kill Value (MVP/Solo): ~9,700 GP.

Conclusion

Scurrius, the Rat King, is a fantastic addition for mid-level players looking to practice core PvM mechanics in a forgiving environment. The fight offers great combat XP rates, especially with the rat bone weapons, and provides a solid introduction to prayer switching, AoE dodging, and add management. Whether training combat or farming for the unique spine, Scurrius offers a fun and accessible boss challenge right beneath Varrock!

Need better gear or combat stats to take on Scurrius more effectively? Check out our OSRS Gold page or level up quickly with OSRS Skilling Services!