That if you ate the pips from an apple core
An apple tree would grow in your belly really really slowly and eventually you'd die horribly with branches growing out of your mouth. I ate a whole apple core once as a playground dare when I was about 6, and spent the next few months awaiting my imminent death.

Also, as a child I had bunk beds (for no apparent reason, as I had a room to myself). I slept on the top bunk and was utterly convinced that Grotbags from the Rod Hull & Emu show was laying on the bottom bunk, and if any part of my anatomy dangled down she would rip it off and eat it. Many's the night I pissed the bed as I was too scared to climb down the ladder to go to the toilet.
(runawayscreaming I'd like to thank the Academy..., Sun 22 Jan 2012, 9:59, 4 replies)

YES
to the first bit.
( Herb Alpert's Taxi Driver I have very beautiful lips, Sun 22 Jan 2012, 19:54, closed)

Don't know how reliable this is.
blogs.discovermagazine.com/discoblog/2009/04/13/too-strange-to-be-true-tree-found-growing-in-mans-lung/
( The Awful Puppy Bakery is still bored, Sun 22 Jan 2012, 20:16, closed)

It's on the internet....
therefore I believe it.
(runawayscreaming I'd like to thank the Academy..., Mon 23 Jan 2012, 2:38, closed)

Grotbags?
I never knew who was down there, but I also refused to encroach past the boundaries of the top bunk. When I did leave safety, it was by leaping from the top so that the element of surprise would enable me to reach the door without my feet being grabbed.

And again, yes to the apple tree.
(Frakkus is blowing bubbles in the bath, Mon 23 Jan 2012, 12:50, closed)