Created by Demon-Man.
Furaffinity: https://www.furaffinity.net/user/demon-man/

All of Demon-Man's works take place in a fictional setting called Belial, where people can transform into bizarre sex creatures if they touch the sexual fluids of demons.
This sequence was posted in an old Yahoo Groups site, with the following descriptions for each image:

1. A young girl from Jizza called Christine who decided to transform herself piece by piece, every day until christmas. This is the last picture of her before she begins with the first change...

2 ....starting with her nose...

3 ....and then changing her mouth. Her new facial vagina has no clitoris, instead her new nose has taken that position.

4. Next are her fingers...

5 ....and her toes.

6. Afterwards she gives herself two more breasts...

7...and a penis between the legs. She gets so aroused she has her first male orgasms with her many penises.

8. Then a new penis grows right above her butt...

9....while her arms split up and turn into ten cock-tentacles.

10. She also grows two new breasts...

11....and her nipples turn into cocks.

12.The same happens to her ears.

13. Today her belly suddenly expands into a pseudo-pregnant shape while her head loses all its hair. In exchange her bodyhair is growing faster than usual.

14. In exchange for her hair, her head grows a nice bunch of breasts...

15. ...and a vagina between her upper pair of breasts.

16. Today she "only" grows a second penis between her legs. Both quickly multiply in size.

17. Furthermore her dicknipples suddenly enlarge, too, and basically absorb her boobs, turning them into large, erect penises.

18. Suddenly her cheeks blow up, distorting her remaining face. At last a hole appears below her vagina-mouth. In fact she has grown a full butt, even with an anus, where her chin had once been.

19. Today's serum makes her new chest-penises and also her crotch-penises all flexible and serpentine. In the end they have become tentacles similar to her former arms...

20. ...while the breasts on her head start to multiply until they cover almost her entire back.

21. Finally her legs suffer the same fate as her arms and split into ten penis-tentacles. Her many cocks start to randomly ejaculate, too, keeping her in a constant state of orgasm.

22. The final stages of her transformation have begun. Christine wouldn't be able to stop the changes now, even if she wanted to. Her heavily transformed head sinks down and fuses with her chest. The pussy between her former breasts changes position, too. It moves abover her facial butt. It grows its own cock takes position next to her original facial vagina. Both then swallow her eyes and replace her lids.

23. Today her belly suddenly collapsed, leaving her "face" directly connected to her many tentacles and breasts. The mass of her former belly changes into a large scrotum filled by dozens of testicles hidden behind her penis-tentacles. Furthermore her nipples change into cocks.

24. Finally her transformation comes to an end. Her backside's breasts change into additional penis-tentacles while her facial genitals disappear (except for the dicks which just become tentacles, too). In the end only her butt and dozens of penises remain. There is also an even bigger pile of testicles hidden behind all her tentacles. She is quite happy with her new form although she is not sure yet if she shall keep a female identity or a male one due to her new, physical gender...

25. But a christmas-demon comes along and turns her into pure tits and pussy. (Picture currently missing, I'll add it here once it's found.)