Why this trick should be IMPOSSIBLE ft. Rodney Mullen - Skateboarding Science

Hi Physics girl, I have two questions that have been haunting me for years, 1) what makes cereal flakes to attract each other when there are a few floating in the milk?, principally the nesquik ones.  2)why? when a pen is running out of ink is when it writes better? The ink comes out more easily and the written lines are almost bold, and then there is no more ink in the ink refill. I hope these questions may be useful for new videos. Greetings!!!