1) Platypus was a progressive rock supergroup that consisted of members from Dream Theater (John Myung, Derek Sherinian), King's X (Ty Tabor) and Dixie Dregs (Rod Morgenstein).
The group was formed in 1997 and disbanded in 2000. There are two follow-up projects: The Jelly Jam, effecively Platypus minus Sherinian and Jughead featuring Derek Sherinian, Ty Tabor and Matt & Gregg Bisonnette. 2) Platypus was a little known, short-lived disco-funk band that was active in the late '70s and early '80s.

Read more about Platypus on Last.fm.