Japanese sentence. what does it mean?

Question:

My friend wrote this "×なっと　○なっとう=納豆"
Kakeru. Nattou=nattou?

What is he saying??
I posted a video of me eating Nattou and this was his reply.
I noticed it's written natto and nattou. whats the difference?

Answer:

Nattou is Nattou. Natto is just spelled wrong and doesn't mean anything. You're friend is probably just trying to point out the difference to you.