The Motion-Sensor Bomb is a small item that has very basic function in both SSF games: when set down, it sticks on the ground remaining immobile, if something touches it, whether it is by a player, an attack or another item, it will explode, dealing great damage and knockback. Due to the flawed physics of SSF, getting hit by the complete hitbox of the Motion-Sensor Bomb deals above 400% of damage and is sometimes guaranteed to KO the character; this, of course, is something that was toned down for SSF2, where a thrown Bomb deals 11% and the explosion 32%, but still dealing great knockback, capable of KO'ing above 30%. In SSF, as it is in Super Smash Bros. Melee, the Motion-Sensor Bomb sports its design from GoldenEye 007; for SSF2, it now sports a custom design that is still very reminiscent to Golden Eye 007's.
The original Motion-Sensor Bomb comes from the Nintendo 64 game, GoldenEye 007, where it is called Proximity Mine. The player simply throws the mine on any surface and waits for the enemy to walk by it. If the enemy gets too close, it explodes and causes powerful splash damage, enough to easily kill the victim. It is also possible for the same person to be killed by his/her own Proximity Mine. The Proximity Mine got renamed to Motion-Sensor Bomb for its appearance in Super Smash Bros., though it got briefly renamed back to Proximity Mine in the PAL version of Super Smash Bros. Melee.