Poppy is a flower that is not present in any known AU.
Poppy appears to be pretty psychotic. She has a beaming smile along with 2 eyes with one being smaller. She has a leaf falling off of her lower petal suggesting some incidence happened with her. She also has an over-grown stem near the bottom of her roots.
Differences to Flowey
The only difference known to this character from Flowey is her Appearance. There is also an image online where she says "Greetings, i'm Poppy, Poppy the Flower".This is obvious that a difference to Flowey is that she says greetings.