Saw

Haven't taken any photos outside today, too horrible for that!

This is the saw from a Sawfish which is a type of ray.

The fish uses the saw to dig around in the sand for prey and to slash at it when it finds it. It also has electroreceptors which can detect creatures buried in the sand. All the species of Sawfish are endangered.

The teeth are actually modified scales and the whole saw feels slightly soft rather than bony which is what I originally expected.