Paints, what do you make of the Aurora Australis and mammatus clouds etc?

Mammatus clouds are the best.  The first time I saw a really good example was just after the tsunami in 2004.  It was on the 27th of December, my nieces birthday and I was at her party.  I took a great photo but I lost it after a computer crash.

I do think that these really strange cloud formations are formed by a number of natural occurances.