Why does this harm the person who pressed the key rather than hurting the person that is touched?

Why does this hurt the player that pressed the key rather than the person getting touched. I don't want the player who pressed the key to be harmed. This script is cloned into a part that shoots. When the player presses a button the part is fired

function onDamage(Part)
    if Part.Parent:FindFirstChild("Humanoid") ~= nil and Part.Parent.Name ~= script.Parent.Name then
        script.Disabled = true
        f = Instance.new("Fire", Part)
        f.Color = Color3.new(1, 0, 0)
        for i = 1,25 do
            f.Size = f.Size +0.25
            Part.Parent.Humanoid.Health = Part.Parent.Humanoid.Health -2.5
            wait(0.05)
        end
        Part.Parent.Humanoid.Sit = true
        f:remove()
        script.Parent:remove()
    end
    wait(0.025)
end

script.Parent.Touched:connect(onDamage)