Walking drum
Walking drums are a seemingly pacific species found only in the PlayStation version of Rayman, more precisely in the first level of Bongo Hills. They have the appearance of a grey drum with swim fins and a diving mask, and they freely wander on their platform, turning backwards when they face an obstacle. When Rayman jumps onto them, they stop moving and let him bounce on them. They cannot hurt Rayman.
Oddly, in Rayman Designer and the other games with a designing tool, these drums are classed as 'Enemies', though they do not hurt Rayman in any way.