The Oski Yell is the University of California Berkeley spirit yell from which Cal's mascot, Oski the Bear, derives his name. Although Oski appeared in 1941, the yell was first performed around the turn of the 20th century. The yell's origins are uncertain, although the University of Illinois originated a similar yell in 1911 (with a different last line). Another early version is credited to Vince Wirtz, who led a similar cheer beginning in the 1920s at football games for Hamilton, Ontario teams.