Wait, why did this catch fire?

Mundane Pointless Stuff I Must Share (MPSIMS)
#1

Someone heats wax in a test tube until it’s boiling. The test tube is then immersed in cold water and the paraffin autoignites? WTH?
Paraffin Wax Autoignition - YouTube

#2

My best guess is that the paraffin vapor was hot enough, but it wasn’t well-enough mixed with the air. Putting it in cold water created sudden turbulence, which mixed the vapor and the air, which then led to the ignition.

#3

Was thinking that the immersion in cold water caused the condensation of one/some paraffin fractions which were inhibiting the ignition of the paraffin vapour.

#4

That was my WAG too: the “correct” stoichiometric ratio was achieved.