From the Super Mario Wiki
Sir Steal-A-Lot is an enemy in the game Wario: Master of Disguise. They appear in both Carpaccio's Lab and Allergia Gardens during Wario's adventure there. They appear to be Sir Worth-A-Lots that carry a sack on their back. If they spot Wario, they will attempt to run away. If Wario manages to destroy one, he will be awarded with many gems that the robot had in its bag. It is possible to get extra gems from these enemies by using the weakest attacks, such as jumping on their heads; every time they are bopped, one gem will fall out of their bags.
Armor containing the soul of James, the greatest thief to ever live. Great at stealing, that is. Not quite so hot at the whole "escaping" part.