Hot was a non-canonical story published in Hellboy: Weird Tales #2, the story is by Randy Stradley and art by Seung Kim.
Plot Synopsis
Hellboy visits Shuzenji, Japan in 1967. While there he is asked by the mayor to investigate the town's rejuvenating hot springs since a number of tourists have gone missing while using them. Upon entering the hot springs Hellboy is greeted by a very forward, naked, female bather. Upon getting too intimate with Hellboy and being rebuking by him she reveals first, that she knows who is father is, and, that she is in fact a giant monster. She pummels Hellboy for a bit but then decides to end the fight and leave the hot springs out of respect for Hellboy's family line. She claims that her departure will put an end to the rejuvenating properties of the hot springs.