Unidentified creature

Unidentified creature

Observation - Unidentified creature. Description: I originally posted this in Other Organisms. I'm posting it again here to Invertebrates to see if anyone here can help with identification. I came across a few of these strange looking things washed onto the shore on a Brittany coastline, back in 2007.

I originally posted this in Other Organisms. I'm posting it again here to Invertebrates to see if anyone here can help with identification.

I came across a few of these strange looking things washed onto the shore on a Brittany coastline, back in 2007. I've always wondered what they might be.
They are quite large - probably between 8 - 10 inches long, and have semi-transparent skin in some parts. As you can see in the pictures, they have a shiny dark rounded point at one end and are fatter at the other end, with a protruding part. There is a dark textured covering over part of them.
They're very alien looking and were quite disturbing to come across!