cumulus arboreus
a lightning strike is often shaped like a tree, with a thick main stem, spreading out into fine branches.
Let's add leaves to it :)
There's a small story about it, you can tead it on my page: https://www.aerroscape.de/imagination-of-nature-en/imagination-of-nature-sea-land-and-skyscapes/2014-and-earlier/ (scroll down a little)