Spawn below you and Tweening Part Size

how to make a something:Clone() and tween the size

--First, clone your part, and store it in a variable.
local clonedPart = something:Clone()
--You can set whatever position and stuff you want to it

--Tweening stuff
local tweenService = game:GetService("TweenService")
--Fill in your tweeinInfo, search it up on the developer hub for a better explanation
local tweenInfo = TweenInfo.new()
--Set the goal of your tween, what you want to tween towards, in this case, a certain size
local goal = {Size = Vector3.new(SOMESIZE)}

--Create the tween
local tween = tweenService:Create(clonedPart, tweenInfo, goal)

--Play the tween
tween:Play()

how to set the positon under the character

You first find the player’s position, probably their HumanoidRootPart’s position.

local playerPos = player.Character.HumanoidRootPart.Position

And when you’re setting your part’s position, set it to the player’s position, but subtract the wanted distance on the y axis.

part.Position = Vector3.new(playerPos.X, playerPos.Y - 10, playerPos.Z)