Question: what are the weirdest thing you've seen in nature?

Steven Thomson answered on 17 Jun 2015:

The weirdest thing I’ve ever seen is a substance called ‘superfluid helium’. When you cool helium gas down, it condenses into helium liquid. When you cool it down further, it turns into a quantum superfluid.

Superfluids can crawl right up the inside of a cup and spill over the edges, or can pass right through seemingly solid objects. It’s incredibly strange stuff!