Studies of the socialization of novices into scientific cultures typically emphasize official knowledge-making activities. However, scientific socialization is also accomplished informally through humor. As entextualized humor, formulaic jokes enable U.S. undergraduate students in science to claim scientist identities both through a displayed orientation to scientific knowledge and through the cultural practice of circulating humorous scientific texts. In response, recipients may align or disalign with these identities and thus position themselves in relation to science cultures.