Can my mom take my kid from me?

I have a very controlling mother. She just got divorced and is retired. All she wants to do is spend time with her grandkids and nothing else. I feel very smothered by her. At times, if I ignore her she will just show up at my apartment and try to take my kid with her. She literally gives my kid everything she wants. If my kid wants marshmellows for breakfast she will give them to her. I havent really spoken to my mom now in over a month. She accused me of being jealous of her because supposedly my kid loves her more. She says that I'm wicked because I dont let her love my kid just because I don't let her give my kid everything she wants. Anyway, my fear is that she will go to the extreme and try to take my kid from my husband and I. Can she do that?