local goals = {["CFrame"] = part.CFrame * CFrame.Angles(0 ,math.rad(180),0)}
You were nearly there, CFrame is both a property name (in this case one of the properties you are attempting to tween) and a custom userdata/value type. Due to this, the field must be stored as a string value like in the above, so that the script doesn’t confuse it with a reference to the CFrame class.