I still haven't found it BUT I looked into the Pokedex and figured out it's somewhere going to the Safari Zone.
cliff cave is right next to cianwood city through the cave
You can find a Steelix in Route 47, Cliff Cave, Mt. Silver, or you can trade any Pokemon with Jasmine.
You can battle wildOnix in/at:Union Cave, Mt. Silver, The Cliff Cave, Rock Tunnel, Victory Road, Safari Zone
You can catch a Misdreavus on Mt. Silver, The Cliff Cave, or the Safari Zone (has special requirements).
Cliff Cave is near Cianwood City. Just go in the cave you see and you'll be in Cliff Cave. When you pass through Route 47, and see many Cave entrances, that will also be considered Cliff Cave.
Misdreavus can be found in Mt. Silver or Cliff Cave.
Machops can be caught in Mt. Mortar, Cliff Cave, Rock Tunnel, and the Safari Zone.
safari zone, cliff cave, and mt. silver-nighttime it is rare in these areas so you may have to look for a while
Use Rock Smash on rocks in the Alpha ruins zone & in the Cliff Cave located on Route 47.
Pokemon Crystal is a Generation II (Gold, Silver, Crystal) game. Absol is a Generation III (Ruby, Sapphire, Emerald, Fire Red, Leaf Green) Pokemon. You cannot get Absol in Crystal. However, you can get Absol in Heart Gold, Soul Silver at: Slowpoke Well, Union Cave, Mt. Mortar, Dark Cave, Whirl Islands, Mt. Silver, Ice Path, Cliff Edge Gate, Cliff Cave, Diglett's Cave, Mt. Moon, Cerulean Cave, Rock Tunnel, Seafoam Islands, Victory Road, Tohjo Falls. But you have to be listening to the Hoenn Sound on your radio.
The Silver Cave is located in Mt. Silver in which you can go after you get all the Johto and Kanto badges. In the Silver Cave you can find lots of strong Pokemon and fight the final boss, Red at the top of the cave.
You find a misdreavus inside cliff cave