Sea cucumbers are versatile creatures. Some species can actually feed with filter feeding apparatus inside their anus (shown below). If you're not feeding from the front there's always the other end...
it turns out that this serves a vital function to ecosystems in both shallow and deep-sea ecosystems (see the secrets of sea cucumber poop here! ) Sediment is aerated and "turned over" and doesn't just build up anoxic organics... etc.
here is where it all starts!
Some nice video of a Japanese species showing aforementioned feeding tentacles which are used to pick food off the substratum