Sleeping Spear Guy
From the Super Mario Wiki
A Sleeping Spear Guy is a pink Spear Guy that is asleep on a platform, it appears in Mario vs. Donkey Kong. Whenever Mario jumps on the same platform, the Sleeping Spear Guy awakes and runs toward Mario. However, if a Mini Mario jumps onto the platform, the Sleeping Spear Guy will not be awoken. Whenever they get to the end of the platform, they will sit down and fall back to sleep.