King Boo (Final Boss)
Before fighting the final boss, I recommend grabbing a Gold Bone from Professor E. Gadd’s lab. One or two should be enough! This is a long and tough boss with some randomness, so it helps to have a little extra preparation.
King Boo has a variety of special attacks. He’ll launch fireballs, summon lighting from the sky, and launch a giant spiked ball full of bombs. To dodge his spinning tongue attack, just time it so you run under the tongue when it’s at its highest point.
To damage King Boo, you need to wait until King Boo throw a spiked ball full of bombs. Grab the non-flashing bombs (they won’t immediately explode!) and shoot them back at King Boo. While he’s stunned, Suction his tongue with both Luigi and Gooigi! Then you can smash the giant boo.
Things get trickier after that. King Boo will summon a copy of himself, performing all of his attacks with double strength. In the third phase, you’ll have to dodge triple the amount of attacks. He uses all the same attacks, but he does get trickier — in the second and third phase, King Boo will have a false copy. Throwing a bomb at the false copy will make him disappear, but won’t hurt King Boo.
As far as I know, there is no way to tell the real King Boo from the fake. You just have to guess — luckily in the second phase, you have two bombs. Throw them quick and you’re guaranteed to hit the real King Boo. The third phase isn’t as easy.
In the third phase, you only have four minutes to defeat King Boo. If the timer runs out, you’ll lose instantly. King Boo will throw spiked balls filled with spikes way, way more often — you need to grab the two non-exploding bombs and guess. You just have to cross your fingers and hope you’re hitting the real King Boo.