I dunno where the ubiquitious "troll face" meme originally came from, but it seems to fit so well in the "Three Billy Goats Gruff" tale.
TRANSCRIPTION COURTESY OF JOSEPH HOUK - (MG, with Cassie in a book store) "Whoa... $350 for an old children's book?" (Shop owner, reaching up for the book in the Rare Books aisle) "That's the first English edition of Norwegian Folk Tales, published in 1879 and featuring the 'Three Billy Goats Gruff' among others..." (CW) "The Three Billy Goats Gruff? Wow... I haven't read that since I was a kid! [pause] No pun intended..." (SO) "This book holds the first illustrations of that tale, done by a team of talented artists." (CW) "Cool! Hey... Something looks way familiar... [The illustration of the bridge has a face on the edge... a Troll Face!] Oh Lord, Matt... Don't tell me YOU were one of the illustrators..." (MG, with a toothy smile) "U JELLY?"