My older brother used to tell me all the time that there was a witch who lived in milk and every time I drank it, she'd go down into my belly and cut me with her long fingernails while laughing her wicked laugh (which he'd demonstrate, laughing witchily and clawing his fingers in the air). I was terrified of drinking milk for years.
I asked him once why he could drink it in tea without the milk-witch bothering him and he said the milk witch died when poured into hot liquid so she couldn't hurt him.
Everyone in my family still has a laugh about this now and again...
A childhood belief about witches

others believed things like this
- that black women breastfed chocolate milk instead of white milkAnon
- I used to beleive that milk bottles were filled with milk, directly from the cow's udder.Anon
- When we were little my sister thought if you mixed cow’s milk and water you’d get goat’s milkAnon
- My Granny said if I drank milk and ate fish at the same time, I would die.Anon
- I used to believe I could milk dogs like the cows. This was because I saw a nurse milk his cow.— Laurent and Alexis, French students in eighth grade
- I didn't believe that a cow's milk and the milk in the fridge were at all related!Anon