Found this on Dawlish beach on Saturday afternoon and wondered what it might be. Probably 12 inches in length.
No interactions present.
Fleshy bit looks like siphons(fused) of a clam, eg http://www.ispot.org.uk/node/289775 , such as Mya species,& http://science-rrhs.wikispaces.com/Bio+Diagrams .
... it does indeed ... that's fascinating, thank you. I have another mystery to post in a short while.
Lat/Lng: 50.5812, -3.4652
OS grid ref: SX963767
Beach in front of railway station