Bomb blocks are a type of block in the Subspace Emissary mode of Super Smash Bros. Brawl and the Bonus Game of Classic Mode in Super Smash Bros. Ultimate. When struck by an attack, a bomb block will explode and destroy nearby blocks in a set pattern, which generally involves a chain-reaction that clears a path. This mechanic is commonly used to clear obstacles in the Subspace Emissary, though at times it simultaneously acts as a hazard, opening a path while destroying the floor for example. Unlike the bomb blocks that appear in Green Greens, these bomb blocks deal no damage to neither players nor enemies. In Brawl, the standard design of bomb blocks are typically labelled with hazard stripes and a round design in the center, though there is also an alternate appearance of bomb blocks exclusive to Subspace levels, which are translucent and purple. In Ultimate, they are always a translucent pink, and feature a diamond-shaped outline on their surface.
Attacking one block to set off a chain-reaction destruction of other blocks is a staple of the Kirby series. In various cases, Kirby can hit a bomb block to clear a path or expediate the destruction of a cluster of regular blocks. Some bomb blocks also have the unusual ability to create unbreakable blocks in chain-reaction patterns, often used to close recently-opened paths or act as a trap that blocks off a collectible. As these bomb blocks feature in the Super Smash Bros. series, these bomb blocks likely serve as the origin for the bomb blocks in the Subspace Emissary.