Sherm

Sherms are tank enemies that appear in Super Mario Odyssey. They are green with Bowser's emblem printed on them, and fire pearlescent blue explosives. and can be found in the Wooded Kingdom, the Metro Kingdom at nighttime, and the Underground Moon Caverns in the Moon Kingdom. When captured with and controlled by Cappy, the player can aim its cannon with the right joystick (as well as by tilting the Joy-Con/Pro Controller), and fire explosives with. The explosives can also be used to collect items. They are used to defeat Mechawiggler.

They are likely named after the American tank, used extensively in  - the hat they wear even resembles the Ascot top hat worn in depictions of.