Slavin, David. Odd gods #2

"Sometimes it feels like Oddonis can't do anything right. Especially compared to his literally perfect twin brother, Adonis. But this time, Oddonis has really messed up by accidentally turning his father, the all-powerful king of the gods, Zeus, into a giant baby. Now it's up to Oddonis to assemble a team of his odd friends--Mathena, Gaseous, and Puneous--and journey to the underworld to get the curse reversed. Along the way, Oddonis will have to overcome a series of dangerous obstacles, his obnoxious brother, his own self-doubt, and the horrible scents of his best friend Gaseous. Can Gods as unlikely, unusual, and unheroic as Oddonis and his friends really save the day?" --