They are having a whale of time! 
...seriously, where did the whale come from...?
It's a toy - both pieces came from one and the same toy, a whale with a shark-like dorsal fin. When you pressed the fin the maw could open and shut. I just cut it in half (removing the fin and internal mechanism, fixing the jax in the open position and a general filling in of screw-holes etc.) and based both halves. After that just priming and painting as usual.
It was a bit of a last-minute backup solution to fullfull the 'large creature or ship' bonus requirements. I did buy an Ainsty ship, but ran out of time to finish it properly. When I saw the toy in a thrift store I snapped it up and with a few hours work it became the 'whale-things' from the picture. I think I paid max. 2 euro for the piece.