nightshade

I don't know, but it will be fun to watch it grow.

Maybe Datura, a member of the nightshade family. They do come up as weeds. https://en.wikipedia.org/wiki/Datura

The leaves look different. Let us see as it grows ...

Are you from South India (your name is common in Tamil)? If you are, you should know it as Manathakaali!

No I am not from the south but it is a Sanskrit name so it could be common across India. Not very familiar with Tamil. It does seem to be some kind of night shade. It is just beginning to flower.

I've looked at your photo several timesnow and I agree that it looks like a Datura. There are many varieties and as yet I don't have a guess as to which one. The flower will tell us what it is.

The plant now has tiny flowers. Some kind of night shade. Wonder how it got here

Definitely black nightshade. http://ipm.ucanr.edu/PMG/WEEDS/black_nightshade.html

It is a weed here, but easy to control. The little berries are edible when ripe and the leaves can be cooked. https://food.ndtv.com/food-drinks/cooking-with-manathakkali-try-these-easy-homemade-veg-manathakkali-recipes-2249565

It looks like it could be a rather nice plant in it's own right. I had a Datura writii that most would consider a weed, but made a magnificent plant in my garden. After 8 years it died. I'm hoping, maybe, that one of her seeds escaped my notice and might sprout me a new one.

This seems to be native here. I have no idea how it got here. Only problem is that it is growing in my Jasmine pot!

You could pull the works out of the pot and separate the two plants...or just cut off the stuff you don't want to grow. and if it comes back from the roots, just cut it off again! ;-)

-Babka