"I'm in Love with a Monster" is a song recorded by American girl group Fifth Harmony for the computer animated fantasy-comedy film, Hotel Transylvania 2. It was written by Harmony Samuels, Carmen Reece, Sarah Mancuso, Edgar Etienne and Ericka Coulter with production handled by Samuels. It was released to digital retailers on August 14, 2015 through Epic Records and Syco Music and serviced to contemporary hit radio in the United States four days later on August 18. "I'm in Love with a Monster" is a pop song that blends elements of R&B, soul, rock and hip hop with "jazzy" rhythms along with heavy and funky beats. Critics drew comparisons to the musical style of girl groups such as The Supremes.

Who sings i'm in love with a monster in hotel transylvania? OK. Let's think. My stream of consciousness:
To answer the question, consider the following: "I'm in Love with a Monster" is a song recorded by American girl group Fifth Harmony for the computer animated fantasy-comedy film, Hotel Transylvania 2. The answer is Fifth Harmony.