From the Super Mario Wiki
The Kab-omb is a variety of Bob-omb, appearing only in New Super Mario Bros.. It has a black face just like a Bob-omb, except it has smaller circular eyes, big blue lips, and slightly smaller feet. It also has a green fringe around the bottom of itself. Kab-ombs can be taken out by Jumping on them; however, if struck by fire, such as a Fireball or Raining Debris, they will light their fuse and run around at increased speed for a few seconds, before jumping upwards and exploding into fireworks. The only stage they appear in is World 8-8.