>>38486040The rafflesia flower on its back grows more with the additional energy that Venusaur obtains when it Mega Evolves. The flower gains a large stem and a few little planty vines surrounding it, almost like a tree in a rainforest. As the rafflesia plant grows, the leaves that were previously attached to it as a regular Venusaur become attached to the vines instead.
Venusaur grows additional foliage on its back (where the rafflesia previously was). However, that foliage doesn't receive a lot of sunlight due to the shade so it is a dark green. As the rafflesia fully matures, it starts to reproduce. Two immature rafflesias develop on Venusaur's head and back, respectively. Venusaur's legs become stronger and thickened with muscle to support the heavier load on its back. And the green spots on its face are additional grassy material that sporadically formed.
