I went as beetlejuce a few years back - its an easy costume - get a black or dark suit from a thrift store, mask off lines with masking tape, paint in between with anything, I think I had used interior laytex, doesn't matter how bad the lines are and in fact it looks better a bit diluted so its not bright white - pull the tape when it is dry - suit becomes a bit crunchy, but its only for one night. For the hair, I actually just used watered down kids white glue and a hair dryer - washed out just fine and 10 years later I still have hair..
you can spray the hair whatever halloween colour you want, think i used silver and white - then you just need some grease paint for the face - it is an intense look and was one of my best costumes ever...
Cheers