Definitely Bert and Ernie in the Egyptian pyramid. That was extremely freaky! Ernie's statue talking back to him and the shadowy sounding echo his "hissing" laugh made! Plus Bert telling him it was just his imagination, it seemed frightening to think your imagination could do such a scary thing LOL. Then to top it off the statue comes to life and starts dancing! Some of the more psychedelic seventies bits scared me too, being a child of the eighties they seemed very mysterious and sinister.