How do i morph the character?

I've tried welding parts from a model to the character, after turning the character invisible, that would work, if it didn't just straight up kill the character.

this is how i welded the parts on the character, is there something wrong w/ it?

T = Dummy.Torso:Clone()
T.CanCollide = false
T.Parent = C
local   w1 = Instance.new("Weld")
w1.Parent = C
w1.Part0 = C.Torso
w1.Part1 = T

I just copied that and changed "torso" to the other parts of the character to morph the whole thing Am i going about this wrong?