What figure of speech is This simply a carnival misery?

The figure of speech used in this phrase is an oxymoron. An oxymoron is a figure of speech that juxtaposes two contradictory terms. In this case, the terms "carnival" and "misery" are contradictory because a carnival is typically associated with fun and excitement, while misery is associated with sadness and pain. By combining these two terms, the author creates a sense of irony and highlights the contrast between the two.