My Neighbor Totoro or really a glorified egg? (need a little mascot costume help)

[KinkyxXxWaffles]

Okay... so, I've made lots of smll craft projects and have lots of experience making large props for cosplays (mostly for other people).
I also am pretty handy with duct tape.

I envision making a Totoro mascot costume with all the fabric used being duct tape.
I have no problem with the duct tape, but creating a base shape gets me a little lost. I've read a lot of threads and walkthroughs on making a mascot head, but my plan for the totoro cosplay is to either have a head piece, a torso piece and a leg/bottom piece that will lock together or a body piece (with a back door) and a removable head.

I just need some advice on creating the frame. I've had chicken wire suggested to me, but a totoro cosplay will probably gather a lot of people wanting hugs and I would think it wouldn't be that great of an idea.

SO- how to make a giant egg shape to live in?

[RyukoKahuma]

foam

[Oshi]

Oh dear lord, you do realize ducttape is a very good insulator, right? Baaaddd idea.

[KinkyxXxWaffles]

I have somewhat of a plan for keeping myself hydrated/not overheated.
(I've been in all duct tape outfits before- just not encapsulated)
Aside from that I'll only be in it for one hour incriments at a time.
trust me- I have this figured out with the duct tape. ^.^;

And I was thinking about using foam, I'm just not sure how to get it in the correct shape (without having to redo sections over and over to make it not bulgy in places, etc.)