This article is from the 2006 series of SMBZ and is no longer canon.
A Bob-omb is a type of bomb used in the paralell universe of the Mushroom Kingdom. Its first appearance was in Super Mario Bros. 2 under the influence of Wart until later under command the of Bowser. This item was used in Episode 1 where Bowser and Kamek interrupted the 5th Mario Kart Grand Prix. There were about eleven of them (along with the Exploding Banana) dropped on the finish line all set to explode.