Imagine you have a toy store, and you want to make it bigger and better.

To do that, you need more money, so you ask your friend YCombinator to help you.

In return, you promise to give them a special kind of toy money that you created (like monopoly money) that they can trade for real toys later when your store becomes bigger and better.

But for now, there are no real toys to exchange yet because the shop is still small and not opened yet.

Now, if you ask other friends for help and give them even better toy money (with better chances to get more toys), you need to tell YCombinator about it.

If YCombinator thinks the new toy money is better, they can ask you to change the toy money you gave them earlier to match the better one.

You have to do this quickly after YCombinator tells you they want the better toy money.

It means that MFN will likely convert very fast, and these 375k will cost you more dilution than you might want otherwise. Or you have to play very fancy sheningans convincing other investors who wanted to be early to wait, just to postpone it and decrease its dilution.