This is an upside down HIBISCUS SCHIZOPETALUS.
I promise I'm not making that up.
I have this plant in my garden. Perhaps it would be more accurate to say that my mother has this plant.
This is the down-side up flower.
This was meant to be the first in an informative series about the flowering plants one finds in lil ol' Goa, but I'm not there anymore.
The wee flower shouldn't suffer though. It's pretty and should be propagated.
According to Wikipedia, the plant is native to East Africa. My guess is an ex-Afrikander (what we call people who lived in East Africa) brought it home and an ancestor of mine got a clipping.
Invasive species? Who knows. I can't see it doing any harm to any local plants, insects or birds. Maybe, like the cashew, the Goan ecosystem can support it.