Barfbat is the type of changer, self mutating tracker. For example, he can fly with the help of wings and strange inflatable tumor-like growths. He can also make a slit appear down his face, resembling a bat's nose and aiding him in finding people with its associated super-smell. This is presumably the source of his name.
Barfbat is an example of a parahuman whose physiology grants him enhanced senses without putting him into a thinker category, the same applies to his enhanced speed, which technically could qualify him as a Mover.
“I know Barfbat. He took us out to eat, remember? The restaurant had chickens in cages just outside the door.”
“Was that him? Right. Well, speak of the devil and he’ll appear.” [...] Kurt waved the others back. Barfbat and the two boys backed off, keeping a respectful distance, so the conversation would be quiet. - Excerpt from Interlude 5x II
↑Barfbat winged his way down. Tumorous, fluid-filled growths deflated and his wings retracted. [...] A slit appeared down the center of his face, and then it parted in layers, each layer adding to a flower-like bloom that was a comprehensive nose that obscured eyes and ears both. Tumors swelled and filled with fluid around his neck and shoulders, stretching out until the skin was transparent, veins standing out where the light hit them.
He broke into a run, arms extending until he could use them to help run, and Jeanne and Kurt both followed. As they reached the outskirts of the little town, they caught up with Kurt’s younger ‘brothers’.
Barfbat had an augmented body, but Kurt and his brothers had efficient movement. Jeanne was fit, she exercised and ran every day, and she could use her power to help traverse obstacles or reduce wind resistance, but it was still an effort to keep up.
They caught up with the thief. It didn’t take long. The terrain was hilly, and that slowed their quarry more than it slowed any of them. - Excerpt from Interlude 5x II
↑“Moose-” Rain started, barely audible. I tensed at his voice, looking up. I motioned for him to continue. “Moose said Barfbat has enhanced hearing and smell.” - Excerpt from Heavens 12.6
↑I shot, one bullet, and that was enough to keep Barfbat from tackling me and getting in close- whatever it was he planned on doing if he managed it. His wings spread, and he flapped, while Chugalug slowly sank below him.
The bullet had made a surprisingly big hole, but that hole was steadily closing, filling up with fluid-filled pustules. What was left as it finished closing was a small patch of what could’ve been the black death. Heavens 12.7
↑Question by braincraft: What classification is used for enhanced or expanded senses? There are a lot of characters in Worm that have something along those lines, and outside of Worm there's stuff like Superman's telescopic vision, x-ray vision, and enhanced hearing, or Wolverine's ability to track by scent.
Answer by Wildbow: Thinker. In some rare cases they'd fall under a Brute classification. - RPG.net comment by Wildbow.