Major Monster Mash

As the last department head falls to your puzzling prowess, you realize there is one last thing you need to do to make the grade: Defeat Dean Martian and save the world!
Make progress by guessing words that can be associated with the word(s) to which it is linked. Explore the graph looking for red nodes; finding them reveals letters in the final phrase. There is no limit on incorrect guesses, so go nuts!