How to draw a person transforming into a chair or jacket?

[Gary N]

I am drawing a manga for a friend of mine and need to draw a transformation sequence for the story. Its a story similer to Harry Potter about a school of wizards. He wants me to draw a picture of a boy being transformed or morphed into a chair and another boy transforming into a jacket (I think a sports jacket).
He wants them for the cover of the piece so I need to do a really detailed shapeshifting sequence. I have done werewolf pieces and another with a tiger but I have never done one of inanimate objects.
I am thinking of doing it in the style of those Animorph covers (like this image http://www.davidmattingly.com/Media/No_MATT_numbers/Anim15lg.jpg ).
But I don't know how to draw a person transforming a chair or jacket. If I draw a chair I guess his head could be the chair rest and limbs the chair legs, but turning into a jacket is more difficult, where would his head and legs go.
If you have any ideas for drawing this piece please tell. Also paste links of similer images.