Bob-omb has two white eyes, a fuse, two legs, and usually has a wind-up mechanism on its back. The mechanism is not required to make the Bob-omb work, however.
In Super Smash Flash
It is one of the many throw-able items featured in Super Smash Flash. When thrown, it has huge knockback, and causes a lot of damage. Because of SSFs damage set and physics, a flaw may cause more than 1000% of damage to occur if a player throws a Bob-omb at a chain of, either, other Bob-ombs or activated Motion-Sensor Bombs with another player standing on them without offering any knockback.
In Super Smash Flash 2
Bob-omb is upgraded in Super Smash Flash 2 to work very similar to its Super Smash Bros. series' counterpart, where it appears as a dangerous item that can be picked up and thrown, they have a small yet powerful explosion on contact. Unlike SSF, if it is left alone for too long, however, it will light its own fuse and start walking around, blowing up when someone touches it, either directly or indirectly, or after a 15 seconds pass. Attacking or hitting the Bob-omb makes it explode instantly so players must be careful. It can do up to 27% of damage.
Bob-omb originally appeared in the non-Mario game Yume Kōjō: Doki Doki Panic under the name Bob (ボブ), with it later being renamed to Bob-omb in the game's localization in North America and Europe as Super Mario Bros. 2. It appears as an enemy dropped by the Albatoss (トンドル) enemy, eventually exploding on its own. Even since its debut, the player could pick and throw Bob-ombs to their advantage, such as using their explosion to defeat other enemies or destroy walls, though the explosion itself is also harmful for the player. Bob-ombs have since become recurring enemies in the Super Mario platforming series, now serving under Bowser's Koopa Troop. They have also become common explosive items in the Mario spin-offs, most notably in the Mario Kart series.