
I googled "pop up flower card" and followed the instructions to create 7 flowers for the most common flower pop-up card you will find on the net. I printed a A4 page of a "Stranger Things" wallpaper for most of the "flowers" but created an 8-petal flower using Photoshop and this image to create the "petals" for the demogorgon:
The pop up 7-flower cards use an 8-petalled flower from which one petal is removed, and then two petals are overlapped, resulting in a 6-petalled flower. So my demogorgon ended up with 6 "petals" (flanges?) instead of the 5 as pictured. But who's counting?
The other 6 flowers I cut from the Stranger Things wallpaper.
If you make each flower from a 3 inch square, the whole "pop up" arrangement will fit in a traditionally sized greeting card - 4 x 6 inches (A6 envelope size). BUT make your demogorgon from a 4 x 4 inch square so it standout out more.
And voila!