From the Super Mario Wiki
Dark Satellmites are dark enemies that assist the Dark Star during the events of Mario & Luigi: Bowser's Inside Story. Their name is a portmanteau of satellite and mite, a small bug. A stronger version of them, Dark Satellmite X, appears in the battle against the Dark Star X in the Gauntlet.
When fighting Mario and Luigi, they will shoot lasers at the bros, but can easily be dodged by jumping. Sometimes, the Dark Satellmites will jump themselves, so their attacks are dodged by not jumping. When they are defeated, they start flashing a red color. When the Dark Star attacks next, it gives a bomb to the defeated Dark Satellmite, which then jumps high in the air with it, and then lets go. Both the bomb and the Dark Satellmite fall towards the bros., who must use their hammers to hit the Satellmite back at the Dark Star, doing damage and causing its spines to retract. After two Satellmite hits, the Dark Star falls to the ground for a few turns and can be damaged, making defeating the Satellmites an integral part of the battle. The bomb the Dark Satellmite drops when it falls is merely a decoy; if Mario or Luigi hammers it it will simply blow up in his face and do damage.
Names in other languages