Timelapse of a sea cucumber feeding. Sea cucumbers feed using "oral tentacles", appendages arrayed around their mouths to capture plankton and other particles from the water.
Video credit: BBC/Blue Planet II
Source: https://www.bbc.co.uk/iplayer/episode/b09gl670/blue-planet-ii-series-1-5-green-seas
Further reading: https://nerdist.com/article/sea-cucumbers-eating-looks-like-an-alien-weird-ocean-creatures/