Boss: Boolossus

Learn how to defeat Boolossus, the giant Boo boss in Luigi's Mansion. This guide covers strategies for each phase and tips for achieving an A rank.

Stats / Weaknesses:

• Boss: Boolossus (15 Boos merged)
• Weaknesses: Unicorn statues (initial damage), Ice element (for individual Boos)
• A Rank Requirement: 90 HP or more remaining

Phases:

1. Initial Form: Boolossus jumps at Luigi. Lure it to a unicorn statue to shatter it.
2. Boo Swarm: 15 Boos fly around. Vacuum ice ghosts, freeze them with 'L', and then vacuum them. The fewer Boos remaining, the more dangerous they become. Use the shoot function (hold 'L' until it clicks) when few Boos are left. Refill ice element by vacuuming a frozen ghost.
3. Reformation: Boolossus reforms, smaller with fewer Boos. It becomes faster but can be held in the vacuum beam. Steer smaller Boolossus onto a unicorn horn.
4. Repeat: Continue phases 2 and 3 until all Boos are defeated. Boolossus gets smaller and faster with each reformation.

Strategy:

• Dodging Boolossus: Run left or right to avoid Boolossus's jumps. Position yourself in front of a unicorn statue and move aside as it attacks to make it shatter. If it heads for your head, change direction.
• Defeating Boos: Vacuum ice ghosts near the unicorn statues. Press 'L' to freeze them, then vacuum. Keep spraying ice to prevent them from attacking.
• Targeting Small Boos: When one or two Boos are left, use the shoot function (hold 'L' until it clicks) repeatedly. Stay at the lower part of the screen to see them clearly.
• A Rank Tips: Avoid vacuuming Boolossus when it's large; run instead. Continuously shoot ice at the smaller Boos to keep them at a distance and avoid attacks, especially when only one Boo remains.