It's scale which is a type of indoor pest that basically sucks the life out of plants. I would manually clean off as much of it as you can with a damp paper towel and then give the plant a nice spray of insecticides. I like to spray a mix of mostly water with a little soap and a little neem oil. It's non-toxic to humans and pets and will not harm the plant at all (but should help get rid of the scale).
Scale is definitely a common pest, Some of my plants get it at least once a year but they do not actually show any signs of damage as long as I take care of it quickly.
Good luck!
-Akex

Scale sucks.

Thanks so much Akex :-)

No problem, hope you get rid of em!
(sorry I made a typo on my name haha)
-Alex