We have a 3 year old boy

I think when boys turn three, there is a superhero gene that gets turned on, as suddenly there is a lot of interest in spiderman, batman, and playing superheroes. Zach has also started asking not just why? but specific - often quite random - questions. Some of the questions I have been asked on the drive home from childcare include:
Why can you only touch jellyfish on the bottom?
Why do we have lips?
Why does soap make bubbles?
Why are octopuses sticky? and, what do octopuses eat?
Why do motorcycles go fast?
Why does Captain Hook have a sword?
What are teeth made of?

I will add to them as I remember...