So, I don't want to give the impression I think something radical is happening here, but there is something that will make you think. If you look closely, whenever the ferrofluid is exposed to flame, the hexagonal grid of spikes changes to a square grid. How do you explain that?
https://www.youtube.com/watch?v=Fw-PemqRN3A
https://www.youtube.com/watch?v=Fw-PemqRN3A