From the Super Mario Wiki
Mini Scuttlebugs are miniature Scuttlebugs that appear in Paper Mario: Sticker Star. They only appear in the World 3 stage Rustle Burrow. Mini Scuttlebugs cannot be battled, but will chase Mario if he gets close to them. If one of them touches Mario, he will move slower and jump lower until it is removed, very similar to Micro Goombas in other games. They can be defeated by hitting them with a hammer, a Super Star, or a stomp. Defeating one will result in getting a Coin or a jump sticker, unless a Super Star is used, in which case only the Coin will drop.