Booth and Brennan investigate possibly the creepiest serial killer they’ve ever dealt with on the Bones Season 11 finale.

I got a look at the season finale, “The Nightmare Within the Nightmare,” and I have to say, this is one of my favorite Bones episodes ever. And that’s saying something.

(Spoilers below!)

Episode description: The team dives back into investigating a serial killer from the past, attempting to find “The Puppeteer,” who lives with his victims’ bodies before disposing of them. Meanwhile, Brennan works through her guilt over her retirement last year, blaming herself for not stopping the serial killer earlier. However, little does she know she might be in some trouble of her own.

As we saw at the end of “The Monster in the Closet,” this new serial killer has their eyes on Brennan — and in the season finale, she learns the killer is obsessed with her.

Of course, I don’t want to give too much away, and trust me, you don’t want me to. But I do have a few extra hints as to what you can expect from the season finale.

1. This is an episode you’re going to want to watch more than once, even though it just may give you nightmares.

2. Brennan isn’t quite herself, and she has Booth and the rest of the lab very concerned about her.

3. Brennan and Max talk about a memory from Brennan’s childhood.

4. Hodgins insists that he’s making a new fashion statement, even though everyone else knows there’s something more going on.

5. Booth and Aubrey witness an extremely weird celebration as part of their investigation.

6. Brennan admits she needs help, and she does something we would never expect from her character.

Check out the video and photos below for more of a sneak peek, be sure to catch the Season 11 finale of Bones airing Thursday, July 21st at 8/7c on Fox!

Promo video:

Photos from “The Nightmare Within the Nightmare”

What are your hopes for the season finale? Share your thoughts in the comments below!

Bones airs Thursdays at 8/7c on Fox.