You can if you want to or you can rent one before entering the festival itself. It's not a requirement.
I went without a costume and I really wish I had one because everyone looked like they were having a lot of fun, definitely not a requirement though!!!
Yes! it's required :) jk you'll have a great time.
It's up to you, wear what you or just dress normal. Half the fun is trying to figure out who works there and who just having fun.
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