Hero crosses his arms and emitting a golden glow around him, becoming intangible for a few seconds. Afterwards, following a dramatic slowdown, Hero explodes, instantly KO'ing himself and dealing massive damage and knockback to all nearby opponents in a very large radius. Said explosion is unblockable, making the move, as its namesake, an effective sacrificial option, though due to Hero being KO'd first, Kamikazee is an ineffective option when Hero does not have at least two stocks. This makes it completely useless in Adventure Mode: World of Light, where all fighters always have only one stock. It's most effective when at high damage, when you know anything the opponent throws at you will kill you, so you may as well deal a lot of damage in the process of losing that stock and even get a KO for it if the opponent is at medium to high damage.
Kamikazee's name is a clue to the spell's effect. As its name (which is a pun on Kamikaze) implies, it involves destroying all enemies at the cost of the caster's life (hence Hero's immediate death). It first appeared in Dragon Quest II, and is often cast by NPC characters and enemies.