Conk was a caveman who resided in primitive Danville who later became frozen inside Danville Glacier around 29,000 years ago.
Conk first lived at around 27,000 B.C., in an area which would eventually become Danville. He was familiar with two boys, Phinabunk and Gerb, who resembled Phineas and Ferb in both appearance and personality, and apparently Conk appreciated their talents as inventors. He was distracted by their "Conga" (automobile) and somehow failed to notice that his foot had become stuck in a glacier until it was too late to remove it. He then remained frozen in the glacier for the next 29,000 years. ("Tri-Stone Area")
Unfrozen by Phineas and Ferb in their garage, Conk picked up English extremely quickly including words like "sandwiches." Conk appeared to be very hungry when Phineas and Ferb took him back to the garage, because he started to try and eat everything. He was eventually mistaken by Candace to be Jeremy in his costume. He disappeared after chasing Dr. Doofenshmirtz disguised as a big sandwich ("Boyfriend From 27,000 B.C.").