It's Toddler Mayham!!

My goodness, is there a gene somewhere in kids that switches on and makes them beat the heck out of their mom?? My daughter has recently begun just pummelling me any chance she has, including in her sleep! She jumps on me, hits me, bites me, and kicks me. And it's not even when she is mad at me or fustrated, it is seemingly for no reason at all! It's all very fustrating. She has the word and the sign for hurt, and she uses both correctly when she is hurt, so I stupidly assumed that she would understand that these thing hurt mommy. Nope, just makes her laugh harder.