I decided to randomly get back on this platform and showcase what I could do; this is pretty bare-bones, as it involves using clones and sine animations. If you don't quite understand how I made the petals shrink/grow, I recommend you use @griffpatch's squish tutorial. It's basically an invisible rectangle within the costume editor for the direction you want to squish the costume, combined with the fisheye effect to manipulate the center of the bulge.
Credits to Rich Werner for the Sunflower sprite from PvZ, rasterized by me. Free to remix for personal use if you want to try it.