So far I'm aware of five titles in Goosebumps Horrorland series:
Goosebumps HorrorLand #1: Revenge of the Living Dummy
Goosebumps HorrorLand #2: Creep from the Deep
Goosebumps HorrorLand #3: Monster Blood For Breakfast!
Goosebumps HorrorLand #4: The Scream of the Haunted Mask
Goosebumps HorrorLand #5: Dr. Maniac vs. Robby Schwartz
At the moment, there is no official book cover for Goosebumps HorrorLand #5: Dr. Maniac vs. Robby Schwartz - so I'm going to draw one myself.
Fun fun fun!
And here is Goosebumps Horrorland video - and that dummy's sure creepy looking!:
And my favorite Goosebumps Horrorland video: Goosebumps Horrorland Movie Trailer