Bass of the River

This is a four-string fretted electric bass, but the body is a bass(fish). When a certain note is played on it, the thing it is pointing at turns into a fish with no way to counter or reverse the spell. This has 10 charges that reset daily. When all charges are used, roll a Wisdom check. If the result is anything below sixteen, this turns into a fish. 

Notes: Vulnerability: Fire, Immunity: Lightning