The mower is a decorative block. It can be opened in order to store 18 items inside of it.
Rotom Change
When a Rotom inside of a Poké Ball is thrown at the fridge, it will become Rotom-Mow and it will learn the move Leaf Storm. Throwing Rotom at it again will revert it.
The Mower can be crafted.
Trivia
The mower has an alternate recipe, as a disagreement within the team stemmed a recipe that used TM129: Rollout for the wheels instead.