How do I make a single script that manages multiple parts in my game?

I have a script that shrinks a part that the player touches. Instead of having to insert the same script in hundreds of different parts (Which creates lag) my goal is to have one single script control all the parts with a certain name (i.e ShrinkingPart) to shrink. This is the script for each part.

local debounce = true
local d = script.Parent.Decal
t = 0.06

function onTouched(hit)
if (debounce == true) then
	debounce = false
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)
	wait(t)
	script.Parent.Mesh.Scale = Vector3.new(script.Parent.Mesh.Scale.x-0.05,script.Parent.Mesh.Scale.y,script.Parent.Mesh.Scale.z-0.05)

	script.Parent.CanCollide = false
	script.Parent.Transparency = 1
	d.Parent = nil
	wait(3)
	d.Parent = script.Parent
	script.Parent.CanCollide = true
	script.Parent.Mesh.Scale = Vector3.new(1,1,1)
	script.Parent.Transparency = 0
	debounce = true
end
end

connection = script.Parent.Touched:connect(onTouched)

You’re wrapping your if statement in brackets, and using deprecated code.

And Dude! You don’t need so many lines!! Use a for loop!

function onTouched(part)
    mesh = script.Parent.Mesh --use more variables !! 
    
    if debounce == true then -- don’t wrap this in brackets!
        debounce = false
        for i = 1, .05, -.01 do
            mesh.Scale = Vector3.new(
                mesh.Scale.x - .05,
                mesh.Scale.y,
                mesh.Scale.y -.05
                wait(t)
)
        end
        
        script.Parent.CanCollide = false
        script.Parent.Transparency = 1
        d.Parent = nil
        wait(3)
        script.Parent.CanCollide = true
        script.Parent.Mesh.Scale = Vector3.new(1,1,1)
        script.Parent.Transparency = 0
        debounce = true

    end
end

script.Parent.Touched:Connect(onTouched)