The man yells, "I'm a Crank... I'm a bloody Crank!" (2.16)
The Cranks are mad in more than one way. They're crazy, yes, but they're also seriously angry. After all, they know they're Cranks, which means that they know they have the Flare.
"Rose took my nose, I suppose." (31.46)
Probably the single best line in the history of literature, this is spoken by a true madman—Mr. Nose, of course. Does what he says actually make any sense? Or it is just gibberish?
"Little booooooy," the man said..."Little girrrrrrrrl. Come out come out make a sound make a sound. I want your noses." (32.16)
This is something straight out of a horror movie or a particularly gruesome fairy tale. It's almost like the kids are being forced to confront their worst childhood fears here.
One of them gagged and spit violently, like he was trying to rid himself of an organ or two. A woman laughed, so full of madness the sound made Thomas shudder. (32.13)
Now that'll give ya nightmares. We don't even know what else to say to that.
He'd seen it back at the window of the dormitory—but now he faced it on a more personal level. Right in front of him, with mo bars to keep them away. The faces of the Cranks were primitive and animalistic. (32.10)
When you see something from a distance, you don't get the full effect. It's only when Thomas sees them up close and personal that he finally realizes how the Flare works: it transforms humans into animalistic creatures.
If he hadn't had the Flare before—a slim hope that Rat Man had lied—he'd surely caught it by now. (34.25)
Thomas eventually start to think he has the Flare. His logic? His life is crazy, so he must be crazy. Think of it: with all of these Cranks running around and all of these crazy Variables, it's pretty hard not to think you're the one going crazy.
"Maybe we can be happy until we're past the Gone." She smiled then, a sickening, disturbing smile. "Then you can kill me." (37.49)
See, this is why Brenda scares the heebie-jeebies out of us. Our guess is that she's not exactly all there, and that the Flare has already started to eat away at her brain.
"I offered you a drink," Long Hair said again, this time any sign of kindness gone from his tattooed face. "It would be very rude to turn such an offer down." (37.37)
Here's an example of someone who isn't completely crazy—but who's starting to go crazy. Long Hair is a Crank who has a sudden mood swing when Thomas refuses his drink; this sudden change in mood isn't normal, especially given how sinister Long Hair's new mood is.
"Nice to meet you ...I'm a Crank. I'm slowly going crazy. I keep wanting to chew off my own fingers and randomly kill people. Thomas here promised to save me." (57.19)
Oh, Brenda, even though you're crazy, you still have a pretty solid sense of humor. (Unlike, ahem, the pretty sane Thomas.)
Thomas screamed before he knew what he was doing. He screamed and screamed and screamed until it finally woke him up. (64.18)
This episode happens right after Thomas dreams of Brenda talking to him telepathically. We're startled because we can't tell if it was just Thomas hallucinating, or if this actually happened. Maybe Thomas has caught the Flare, and he's going cray-cray himself; or maybe Brenda isn't just some random Crank who wants to chew off her fingers and kill people?