That is known as fasciation. Fascinating!

A common example of this in everyday plant use is the annual cockscomb form of Celosia, which looks like a brightly colored brain to me.

It is said to be caused after pruning or spraying the garden with herbicide when its windy.
I wonder i its propagateable?

Well, there is a cultivar of cryptomeria that fasciates regularly. Obviously, it is genetic. There could possibly be environmental triggers (no recent herbicide or pruning of this shrub in my yard, though) to make this characteristic emerge, but it seems there is in some species, like forsythia, a genetic tendency at least. Where there is a tendency, eventually it seems a stabilization of that trait could occur even without a trigger. I actually have two connected branches on the same shrub that look like this. I'm going to try propagating from these branches. Hopefully I will get shrubs that fasciate regularly or shrubs from subsequent generations of cuttings that will fasciate regularly.

I had this on my forsythia also. It reverted to normal eventually - over two years or so. I should go out tomorrow and check to see if there is anything left of it.

I don't see any sign of it anymore.