Boobeam Trap

Buebeam Trap (ブービームトラップ Bu-bi-mu Torappu) is the infamous fourth Wily stage boss of Mega Man 2. This is considered by many (if not most) players as the most frustrating boss of the game, as its only weakness is Crash Bomber and six out of seven shots are necessary to defeat it. There are breakable walls around the screen, but only two must be destroyed. The rest can be bypassed with the three platform Items.

The Buebeam Trap is more commonly referred to as the "Orb Room", especially by fans.

Trivia

 * It's possible to defeat the Buebeam Trap using only six Crash Bombs with careful planning, accurate jumps, and the usage of Item-1.
 * If the player is willing to intentionally die at the boss, it's also possible to defeat it using only 5 Crash Bombs their second visit. To do this, the player must arrive at the boss room and (at the very least) destroy the left-most wall and bottom-right wall, then get defeated.  Afterwhich, they would refill their weapon energy on the enemies between the checkpoint and the boss room.  Upon entering the boss room again, any walls they destroyed their first time around will still be gone.