EDIT: CHANGED THE LOOK OF THE ITEM AND ALSO TEXTURED IT (It no longer look like a crayon!)
This is how the ancient demoman used to catch his fish in the old times.

This is my first item so please don't be too harsh to me.
This would be a melee demoman item.

I had a thought that this could have a different attacking style, as it attacks from the middle of the screen, just like the original does.

There could also be an alt-click function where the demoman throws the spear doing initial damage and damage over time. If the rod were to hit nobody and land on the floor, the demoman will be able to pick it back up and throw it again. (Shown in the last three pictures)

I understand that it is a little big in the picture, but that is just to get the idea there.