Shroob-omb

Shroob-ombs are massive purple Bob-ombs used by the Support Shroobs in Mario & Luigi: Partners in Time. The Support Shroobs toss the Shroob-omb at the Mario Bros., which causes a large explosion that cannot be avoided. After the explosion, another Shroob-omb is dropped into the battlefield by a Shroob UFO. They have extremely high defense and  are programmed to take one damage from any attack. However, if the player does destroy it, the Support Shroobs stop attacking until at least two of the Shroobs are defeated. A Shroob-omb then appears on-screen and either rolls towards the Mario Bros. or the Commander Shroob, as if the Shroob-omb was never destroyed in the first place. Additionally, if the Mario Bros. manage to destroy more than one Shroob-omb, the game awards the Mario Bros. for destroying only one (that is, the brothers will receive 0 Experience and 1 Coin for their efforts).

Three Support Shroobs are needed to lift one Shroob-omb effectively. If one Shroob is defeated, the two remaining Support Shroobs flash red under the stress. After a second Support Shroob is defeated, the Shroob-omb crushes the remaining Shroob, and the Shroob-omb rolls off, either into the Mario Bros. (if the back Support Shroob remained) or Commander Shroob (if the front one remained). The middle one is random. If, however, all three or the remaining two are defeated at the same time, the Shroob-omb falls to the ground and explodes harmlessly.

Dark Fawful Bombs from Mario & Luigi: Bowser's Inside Story bear a strong resemblance to Shroob-ombs. They both are larger than normal Bob-ombs, both are purple, and both are carried by other enemies.

Trivia

 * In the Japanese and European versions of the game, the Shroob-omb has the highest amount of HP of any enemy in the game, including the Elder Princess Shroob.
 * Although the Shroob-omb takes only one damage, its defense is at 95. This is corrected in the Japanese and European versions of the game as its defense is at 999.