The Fenton Ghost Fisher is an invention created by Fenton Works. It is a fishing line coated with a special high-test ectoplasmal resin that ghosts can't break.
In "Parental Bonding," Jack uses it to fish for ghosts in the Ghost Zone. Later, Danny uses it to tie up Sam when she is transformed into a dragon.
In "Shades of Gray," Danny uses the Ghost Fisher as a leash to tie Cujo to a tree to keep him from entering Axion Labs. However, this caused Cujo to drag the tree caring both Sam and Tucker.
In "Public Enemies," Jack attempts to use it to capture Danny Phantom, but is unable to use it as it becomes tangled.
The Fenton Ghost Fisher looks like a normal fishing pole with a glowing fishing line. The pole is collapsible into the handle, leaving a small metallic cylinder.