The Give Yourself Goosebumps series has many mazes and drawings worked into its stories. You can view some of the drawings here. For years, I've wondered who did them. The books don't actually credit the artists!
At long last, I think I've finally managed to crack the case, and the way that I figured everything out was really wild.
I tried contacting Scholastic about this issue, and a representative said that she couldn't tell me who made the interior art. Maybe she didn't even know who did it! I believe the illsutrations were comissioned by Parachute.
After this dead-end, I was pretty much stuck. That was, until I saw this promotional ilustration of Fear Street. That looked strikingly similar to the art from the Give Yourself Goosebumps series! Upon my first inspections, I was sad that the image didn't have a signature. But then I realized, there was a signature printed in the bottom left. I could barely even read it! When I zoomed in, it looked like it said "Morrell".
This seemed like another dead-end. I couldn't find anyone named Morrell who fit the bill. Then I found this image through Google. Once again, I was sad because the image didn't seem to have a signature. But then I realized, there was a signature! It was disguised, written on a tombstone. I could have missed it if I didn't already have a vague idea of the artist's name (from the previous promotional image). This one very clearly said "Merrell".
After some quick Googling, I was able to find the artist for the two illustrations above: Patrick Merrell. You can check out his website here; his art is a near-identical match for what I was looking for, and he specializes in puzzles and mazes. He even lists "Parachute Publishing" as one of his previous employers. Though, he doesn't directly state Give Yourself Goosebumps.
I tried contacting Mr. Merrell a few days ago, hoping to get confirmation. I haven't recieved a response yet. (Please don't go out and message him yourself! I don't want him to get spammed.) Mr. Merrell is a very talented artist, and he deserves credit for his work. The interior illustrations for the Give Yourself Goosebumps books were undeniably a huge part of what made the books so fun and charming for young readers.