A Dr. Jekyll and Mr. Hyde costume could take several forms. A party-goer or trick-or-treater could choose to dress as either Dr. Jekyll, Mr. Hyde or both at the same time. This is one of the costumes that works well for a pair of people; one goes as Dr. Jekyll and the other dresses as Mr. Hyde. Mr. Hyde is described in the novella as being short and extremely ugly. You can let your imagination go and make your Mr. Hyde costume as monstrous as you like.