Many necro spells weren't added until after the pet-daggers nerf (which happened in Jan 2000).
Shadow Compact was one of them.
Full list is in this post. They were all patched in in Feb 2000. We are currently in June 1999.
https://groups.google.com/forum/#!ms...o/89JWKNGoLYYJ
Edit: Screaming Terror was added in July 1999 as compensation for removing Charm/Beguile from necros, check the patch notes. Next month.