Tim Conway credited as playing...
Professor Alexander Graham
- Fred: Look, gang! There he is!
- Mastermind: [being dropped out of the vacuum tube] Whoa!
- Fred: Come on, gang. Let's see who the Mastermind really is.
- Shaggy: Wait, Fred. Like, I know who this guy really is: It's that spooky groundskeeper! Right?
- Groundskeeper: [shows up] Oh, yeah, that's right. Blame the spooky groundskeeper. It's always the spooky groundskeeper. What do you people have against groundskeepers? Some detectives! Why didn't you just say the butler does it? But no, it's always got to be the groundskeeper done it. Anytime ghosts scare somebody off a well-kept lawn, it's just got to be the groundskeeper, like we couldn't just put up a sign that says "Keep off the grass". Yeah, I'll just get myself a big, old rubber monster suit!
- Fred: [clears his throat] As I was saying, let's see who the Mastermind really is.
- [removes the Mastermind's mask, exposing Professor Alexander Graham physically]
- Fred, Shaggy, Daphne Blake: [in unison] It's Professor Alexander Graham!
- Professor Alexander Graham: Oh, me? Heh, heh. Oh, my.
- Holly Graham: Uncle Alexander? I don't believe it!