From the Super Mario Wiki
Sir Shovalots are enemies in the game Donkey Kong on the Game Boy. They first appear in Stage 3-2 on the Ship. Sir Shovalots also appear in Mario vs. Donkey Kong. They will hold their shield up and charge at Mario as soon as they see him. They do not hurt Mario themselves, but they push him away. They can push Mario off the platform he is currently standing on, but they can also push him against a wall, killing him in the process. Sir Shovalots could also push Mario into small gaps while he was ducking, allowing him to access new areas.