When I was about 7 or 8, we had to look up lists of words for homework. One of my words was 'infiltrate' and the definition I found was 'To enter secretly with an unfriendly purpose.' Somehow I misread it as 'To enter secretly with an unfriendly porpoise' and I wondered why somebody had made a word for that, as it couldn't be that common.
A childhood belief about spelling

others believed things like this
- I used to believe that they secretly had school on holidays and that I was the only one who didn't know.Anon
- I thought the word economical was actually two words: eek and omical.
— Nancy M. - I used to believe that the words Angliphile and Francophile were related to the word paedophiles.Anon
- I used to believe that all four-letter words are bad words.Anon
- I used to belive that teachers were evil.....that why they made us do homework.— Lindsey
- I thought a porpoise was the same thing as a pufferfish— Nemo Boy