Conversation so far:
What happened in 1984?
He later joined the musical group World Class Wreckin' Cru under the independent Kru-Cut Records in 1984.
Did they record any singles or albums?
"Surgery".
Did it have any hit singles?
"Surgery.

Question: What happened in 1985?
Self-contained rewrite: What happened to Dr. Dre in 1985?