What's with my cat? Any help?

So my sister and I came home from my dad's house and my sister was wearing a black winter hat

We were laying on a bed talking when all the sudden we hear our cat meowing I've never heard her meow like this anyway she had the hat in her mouth she was running in the bedroom then to the bedroom across the hall then into the hallway and start doing it all over again the whole time with the hat in her mouth she's only maybe 6 months old and it's really weird what is she doing??? She's a really crazy cat though she runs around a lot like she's all cuddly one minute the next she evil and runs around and jumps out at people but she's really sweet when you pet her or she hears the food bag of corse