On-sale date from Comic Reader #161.
With this issue, the series starts the Dollar Comics giant format with no ads for six issues. This issue permanently subsumes the Witching Hour, House of Secrets, and Doorway to Nightmare series. The hosts/characters for those series are here to introduce their sequences.
The original cover logos for Doorway to Nightmare (DC, 1978 series), The Witching Hour (DC, 1969 series), and House of Secrets (DC, 1956 series) occur on the covers of many Unexpected issues from #189 through #205.