That's florges, flabebe's final evolution, despite the planty look its still mono fairy fsr which i find really strange.
Anyway, i did some estimates for Mega Ampharos and heres what i got, pretty rough especially because we don't know what nature it is afaik, but i guess its worth posting either way:
90/63-111/73-121/130-178/63-111/8-56
if anyone figures out what nature mega ampharos has i'll change the estimates to match the nature. At the moment though it looks like Special Attack is getting a pretty significant boost, and that Speed is either staying exactly the same or actually going down upon mega evolution (unless it turns out to be a minus speed nature, if that then its probably staying the same). Bulk may or may not increase depending on evs, ivs, and the like.