Which word describes something fantastic, comically hideous, or strange and unnatural?

The term that best encompasses the idea of something that is fantastic, comically hideous, or strange and unnatural is "grotesque." This word specifically refers to a style or quality in art and literature that evokes a sense of bizarre, abnormal, or distorted beauty, often through exaggeration and vivid imagery. It is frequently used to describe characters, situations, or visual elements that provoke a mixture of fascination and revulsion, tapping into the uncanny elements of human experience.

On the other hand, while "surreal" refers to dreamlike and bizarre qualities that seem illogical or fantastical, it doesn't inherently carry the connotation of being hideous or strange in a comical sense. "Quaint" implies charm and originality, often in a pleasing context, and is generally associated with things that are pleasant or attractive rather than grotesque. "Macabre" relates specifically to the darker aspects of death and decay, invoking horror or the unsettling associated with such themes, but does not encompass the broader spectrum of strangeness and humor implied in the term "grotesque." Thus, "grotesque" is the most fitting choice for describing something that embodies those fantastic, hideous, and unnatural qualities.