A. F. Crumbley was a male peculiar appearing in Hollow City after his death, when Jacob Portman and his friends stumbled upon his corpse in Miss Thrush's Loop.
Miss Peregrine's Home For Peculiar Children[]
At some point Crumbley would flee from his own loop after it was attacked by wights and would flee into London. Through a series of unknown events he would wind up in Millicent Thrush's loop. It is assumed that not long afterwards the loop would be raided by wights.
Miss Thrush and most of her wards would be taken. Crumbley wouldn't be and he seemed to have accepted that he would either constantly be on the run or would be eventually caught by wights, so he decided to commit suicide by aging forward.
For an unknown reason his corpse would wind up in the middle of the courtyard of Miss Thrush's house. An unknown person would put a black tarp over his body. Someone would also insert a note into his shoe. The note read "Mr. A. F. Crumbley, Lately of the Outer Provinces, Aged forward rather than be taken alive, and Kindly requests his remains be deposited in the Thames".
Hollow City[]
Eventually Jacob Portman, Emma Bloom and Horace Somnusson would stumble upon his body. Because of how recent his death was, it looked like he was sleeping, though he had become a desiccated cast of himself. When Emma touched his ear with her boot, he would crumble to dust.