Is this welding?

There are some make your own morphs around, and i modified one to add a backpack and hard hat on spawn. You can use it too.

somewhere in your game place a block called "Middle", Identify the forward direction and set size to (2, 2, 1) This is the torso.

place the backpack behind the torso, make sure it is not called Middle

Make the torso invisible, and group the torso and bricks. call the group "Chest"

Finally, group this (non local) script and "Chest", and call it whatever you want.

(You can also move the model in the lighting or ServerScriptService, as long as the script runs, it will work)

(You can also remove the wait(1) if you want)

function onadd(hit)
	wait(1)
	if game.Players:getPlayerFromCharacter(hit) == nil then return end
	if hit:findFirstChild("Humanoid") ~= nil and hit:findFirstChild("Chest") == nil then
		local g = script.Parent.Chest:clone()
		g.Parent = hit
		local C = g:GetChildren()
		for i=1, #C do
			if C[i].className == "Part" then
				local W = Instance.new("Weld")
				W.Part0 = g.Middle
				W.Part1 = C[i]
				local CJ = CFrame.new(g.Middle.Position)
				local C0 = g.Middle.CFrame:inverse()*CJ
				local C1 = C[i].CFrame:inverse()*CJ
				W.C0 = C0
				W.C1 = C1
				W.Parent = g.Middle
			end
				local Y = Instance.new("Weld")
				Y.Part0 = hit.Torso
				Y.Part1 = g.Middle
				Y.C0 = CFrame.new(0, 0, 0)
				Y.Parent = Y.Part0
		end

		local h = g:GetChildren()
		for i = 1, # h do
			h[i].Anchored = false
			h[i].CanCollide = false
		end
		
	end
end

game.Workspace.ChildAdded:connect(onadd)