When doing :Destroy on a tool it breaks. How do I fix this?

Let's say I wanna delete a tool when I unequip my tool.

tool = script.Parent
tool.Unequipped:Connect(function()
tool:Destroy()
end)

See that would work in most cases because is my other game it works but in my new game it doesn't. In output an orange/yellow message appears:

** Something unexpectedly tried to set the parent of Tool to NULL while trying to set the parent of Tool. Current parent is Backpack. **

I've also tried more options like deleting it from Backpack via :FindFirstChild but that sends the same message too.

Please help me.