Tried this and it is better, but still has the problem of the other parts not sizing up with it:
local balloon = script.Parent.Parent.Parent.Parent.Parent.RedBalloon.PrimaryPart
local tweenService = game:GetService("TweenService")
local tweenInfo = TweenInfo.new(2, Enum.EasingStyle.Linear, Enum.EasingDirection.In, 0, false, 0)
local tween = tweenService:Create(balloon, tweenInfo, {Size = Vector3.new(5,5,5)})
script.Parent.MouseClick:Connect(function(plr)
tween:Play()
end)
Thanks for the help