House of Boom

House of Boom (, Trap Room) is Steve's Final Smash in Super Smash Bros. Ultimate.

Overview
Steve places an oversized piston block in front of himself, which then extends outwards to hit any opponents in range. The first victim caught is taken into a cutscene where they are thrown into the House of Boom, a structure filled with TNT and mobs. Creepers and Zombies attack the victim, producing an explosion. Steve enters the frame and eats a "victory steak", after which the victim is launched. Any other opponents struck by the Piston will take knockback from it. Steve also crouches three times and looks toward the camera upon completion of the Final Smash, akin to his down taunt.

Origin
In Minecraft, pistons are crafted with three planks of wood, four cobblestones, one iron ingot, and one redstone. They can push other blocks, mobs, and players around when given a pulse through a redstone circuit. The giant piston Steve summons in Smash does not naturally occur in Minecraft, and exists solely for the purposes of the Final Smash.

While the House of Boom does not naturally appear in Minecraft, it bears a strong resemblance to both strongholds and jungle temples, structures that naturally generate in the Overworld. The former serve as the only entrances to the End dimension, where the fight against the Ender Dragon takes place (although unlike the House of Boom, strongholds are found underground rather than on the surface) and the latter contain chests guarded by traps. There are other structures in Minecraft that contain harmful traps, such as desert pyramids, structures which contain rooms with chests filled with valuable loot and a pressure plate that can activate TNT hidden underneath, should an unsuspecting player fall onto it.

Masahiro Sakurai stated that the Final Smash was inspired by seeing players create buildings filled with traps to harm their opponents, which consists of an act called "Griefing": intentionally irritating another player. The first-person perspective seen just before the explosion resembles Minecraft's default camera mode, with the irregular movement characteristic of a computer mouse. Steve's crouching after the Final Smash is a common gesture in the Minecraft community used as a sign of friendship or, in this case, to mock a losing player as a form of teabagging.

Trivia

 * The actual "House of Boom" is a pre-rendered cinematic for everything besides Steve and the victim. Noticeable and compression artifacts can be seen during the explosion, and characters who wear dresses or capes will not have their clothes conform to the shape of the floor.
 * This makes it one of four Final Smashes to incorporate a pre-rendered segment, along with All-Out Attack, Gigaslash, and Supernova. Like them, the animation is rendered at 30 frames per second (likely as a space-saving measure), as opposed to the rest of the game running at 60 frames per second. The damage percentages are also absent during these attacks. Unlike the former two, the game can be paused during House of Boom's cutscene.
 * The opponent hit by the Final Smash uses their trip animation when thrown in.
 * Very faintly at the beginning of the Final Smash cutscene, it is possible to hear the 'Cave 8' and 'Cave 17' sounds that play in dark areas in Minecraft.
 * This and Sealing the Keyhole are the only cinematic Final Smashes where the Finish Zoom can happen.
 * However, the latter can only activate Final Zoom in Stamina Mode if the opponent's damage is under 100% due to its Instant KO feature.
 * A glitch can occur in Stamina Mode, where Steve can use his Final Smash on a knocked out character right before they disappear. In that case, the character will not appear in the cutscene.
 * The explosion graphics during the cutscene are identical to those in Minecraft: Bedrock Edition.