From the Super Mario Wiki
Diggas are Bullet Bill and Nosedozer-like enemies appearing in Super Mario Galaxy 2; they are only located in the Spin-Dig Galaxy. Diggas are similar to Ragumos from Super Mario Land 2: 6 Golden Coins, only instead of burrowing underground and attacking Mario, Diggas drill with their body exposed and ignore Mario. They have a yellow body, a drill for a nose, angry eyes, and no arms or legs. They can be easily destroyed by a Jump, a Ground Pound or with a Spin Drill. They can also be summoned by the boss Digga-Leg.
Names in other languages
|hori is related to the Japanese verb horu which means to dig
||It's a mix between "Bohren" (to drill) and "Torpedo" (torpedo)
||From "trivellina", that means little drill
- ^ Super Mario Galaxy 2 Official Prima Games eGuide, page 26.