Dandadan

Dandadan is a Shonen manga and anime series about high schoolers Momo Ayase and Ken Takakura (nicknamed Okarun) who clash over beliefs in ghosts versus aliens, leading them to an absurd battle against supernatural beings from both realms. After a bet to prove each other wrong, Momo is abducted by aliens and Okarun is possessed by a spirit called Turbo Granny, but they survive and ally to face various paranormal threats, from extraterrestrials to urban legends and other creatures known as Umas.