What is the most difficult Pokemon to cosplay as?

[Brendino]

I can only imagine that things without legs or arms would be hard to dress up as. The first Pokemon that came to my mind were Dugtrio, Geodude, Electrode, Solrock and Combee.
I also figure it would be pretty difficult to try and dress up as any of the Unown, considering you would just have to be a giant floating letter, ! or ?

 

[TempestRush]

If you use actual steel, steel type costumes would be damn hard to walk in.