Mustard cress? Garden cress?

"Upside Down Plant" if you ask me!

Or...........maybe one of the chickweeds....;^)

+oM

I'm seeing seed pods. You might want to pull it before seed is dispersed or deal with an ongoing crop....

you can avoid such.. if you sterilize your potting media.. prior to use ... see link ...

you could gently scrape out an inch or so of media [i would just use a teaspoon] ... and replace it.. else.. there are probably a billion seeds in it ...

such things.. usually need sunlight on the surface to sprout ... so by removing that inch or so .... you get rid of most.. and bury the rest ...

it will have no immediate effect on your plant ... i suppose if you left it there for a decade.. and never fert'd.... it could use some nutrients ....

there is a very active houseplant forum ...

ken

Here is a link that might be useful: link

I'd say it's Hairy Bittercress - Cardamine hirsuta. Pull it or mulch it before you have it growing everywhere.