Rose, Walter (1962) The Reptiles and Amphibians of Southern Africa, Maskew Miller, pp. 433-434

There have been, over a term of years, many reports of a snake that has a red comb and wattles like a cock, some of the narrators adding for good measure that it crows like a rooster, that bane of all drowsy suburbanites.
As far a we can gather the story originated in Angola, spreading into South West Africa, and Rhodesia. A good account was sent to use from Southern Rhodesia. Our informant [Dennis A. Walker], when showing to one of his African boys some pictures of snakes, was asked if he had a picture of "the snake with the cock's comb and wattles". When he denied the existence of such a creature, the boy related that one day when hunting in the M'toko range, his dogs surrounded a small tree in which he saw a huge snake, which slid to the ground and raised the fore part of its body after the manner of a cobra, to a height of about six feet. Not surprisingly, he turned and ran, but not before he had seen that the snake's head was adorned with a red comb and wattles like those of a cock.  From further investigation amongst Africans, my correspondent gathered the following  description of the mysterious reptile.
Length about 15 ft., colour a uniform grey or brown all over except for the red adornments, habitat amongst huge rocks on koppies and in the branches of baobab trees, eyes of enormous size, diet mainly dassies, makes two basic sounds, a cheeping not unlike that of a baby chicken and a sibilant whistle. Suggestions that it might crow like a cock were agreed to, but not volunteered. Progressed at times with the fore part of the body raised perpendicularly; greatly feared on account of its size and potent venom, death being practically instantaneous; no super-normal powers were attributed to it, fear being inspired only for physical reasons (Annesley). A careful and concise account calculated to shake the doubt of a sceptic.
Several years ago we received a letter from a German correspondent in South West Africa whose name we omitted to record, stating, "I have now made enquiries about the mythical 'Ondara', a python whose home is in the north of South West Africa(?). One was killed in Groenfontein in 1910 they say. The head was supposed to be like a turkey's with red lobes. The Bushmen refused to skin the animal, so the  farmer had to do the work himself , but he broke out in a terrible rash over his neck and chest and had to go to hospital. I am trying to find out whether the story is true, but a great many of the people concerned are dead, so my efforts to get to the bottom of the story have so far been in vain. I wonder if you know anything about it."