This extremely short and easy script cause an error.
local tool = script.Parent
tool.Equipped:connect(function(mouse)
tool.Activated:connect(function()
print(mouse.Target)
end)
end)
At first when the tool was equipped and activated by a player then the functions work correctly as it should.
But when they reequip it and activate it again. The mouse will deactivate itself and cause an error

1 comment
You need to disconnect the event after its unequipped. The mouse passed it the equipped event will disconnect all events for you when the tool is unequipped.