18 (R U Legal Yet?) is an unreleased instrumental track recorded on 5 December 1988 at Paisley Park Studios in Chanhassen, Minnesota (during the same session as 17 (Penetration), three days before 19 (Jailbait)), during sessions for Madhouse's third album 24. The track was included as the second track on the album 24, before the album was abandoned.
The track includes spoken phrases of "18 (are you legal yet?)" spoken by Eric Leeds, believed to be his only vocal contribution to a Prince-related track, as well as two spoken phrases of "My father has a shotgun" and "I hope he doesn't use it" spoken by Paisley Park Studios engineer Heidi Hanschu.