userId is invalid when passing it to humanoidDescription

So I made a script where the character of a player will change the HumanoidDescription of a dummy, I made this in a local script so a player can only see his character, but I do get this error when passing the userId in the humanoid description : “Players:GetHumanoidDescriptionFromUserId() got invalid userId”

This is the code:

local dummy = game:GetService(“ReplicatedStorage”).Dummy:Clone()
dummy.Parent = workspace
local animation = script.Animation
local animationTrack = dummy.Humanoid:LoadAnimation(animation)
local plr = game.Players.LocalPlayer

dummy.Humanoid:ApplyDescription(game:GetService(“Players”):GetHumanoidDescriptionFromUserId(plr.UserId))
task.wait()
animationTrack:Play()

Do you have any ideas on how to solve it?