Toddlers

How can something so cute act so horribly? My kid is going on three years old and she does such weird things and acts so horribly that sometimes I want to throw holy water on her and say “the power of Christ compells you!” I have taught her to say "please" and "thank you" and "sorry", and she knows when to say them, and she’s normally a sweet little child, but sometimes, out of nowhere, she throws a huge tantrum about something so miniscule. It makes me want to pull my hair out. Is this normal toddler behavior, or do I need the exorcist? I have a feeling I’ll wake up on a dark, stormy night with her standing at my side of the bed with a butcher knife and an evil smile.