Weird thing #2 - What's up with Grover?

I was already having a bad last day because it was my absolute last day...I'd gotten kicked out of Yancy. First of all, Grover (my best friend) kept acting all fidgety on the bus. Grover kept trying to say Mrs. Dodds never existed, but I know that is not the truth. He told me he lived somewhere called "Half-blood," but he said don't say it real loud...I don't know what that's all about! Anyway, while we rode the bus, we saw the craziest looking old ladies knitting the biggest socks I'd ever seen - and they were looking right at me!!! Grover made me promise to let him walk me home. He said he was sent to protect me. Protect me from what???

Weird thing #1: Mrs. Dodds

The weirdest thing happened at the museum today...we went on a field trip and I got in some trouble. Mrs. Dodds told me she wanted me to come with her but she kept disappearing. First, she appeared at the top of the museum steps, and then she appeared inside the museum. It was weird, but stuff like that happens to me all the time. Anyway, she started growling like a monster, and she kept telling me that I had caused enough problems for her. AND THEN...Mrs. Dodds turned into a monster! She had wings and everything. After that, Mr. Brunner appeared out of nowhere with a sword - he killed her!!! After all of that, my best friend, teacher and classmate acted as if nothing even happened!

I gotta figure out what's going on here.

BTW - Mrs. Dodds looked like this: