James Whitfield, who has added some great photos of Abydos to the Photo Album, has a query about the figure in this post:
I haven’t seen any figures like this before that I can remember. I can see the hieroglyphs for Nephthys on the right side of the photo, but I’m unsure if that is referring to the figure. I wish I had a shot that wasn’t as zoomed in as this one, but I didn’t think about it at the time.

By
This 2 headed goose god represents Hapy, the Nile god.
he stands in a shrine with Nephthys.
He is also on the opposite west wall, but with the goddess Maat, where he promises the king “high niles every day, like Re”
These scenes are described by Rosalie David in her book,
“A guide to Religious Ritual at Abydos”
Thanks for the response Peter! Very detailed and complete. I had just never seen anything like that. I’ll have a look at Karnak when I’m there in March. I have the Hornung book too so I’ll read that as well.
There are a few similar deities to this double bird-headed ‘beastie’ in some of the afterlife texts. Most seem to consist of ‘strings’ coming out of the neck instead of a head, but there are also snakes & birds’ heads. Some examples that might be worth investigating are as follows:
In the Amduat
4th division – central register – ‘he who is above his coffin’
10th Division – upper register – ‘the carrier’
11th division – upper register – ‘his two arms are in his body’
12th division – lower register – Nehi
Erik Hornung has described one of these deities:
Erik Hornung (1982) Conceptions of God in Ancient Egypt: The One and the Many, 118-121
In addition, there is a similar deity in one of the chapels at Karnak, on the path running between the doorway between the Forecourt and 2nd pylon that runs northwards towards the Temple of Ptah. There are a number of chapels. One dedicated to Amasis & Nitocris and another dedicated to Osiris-Onnophris Nebzefa, one of these includes a deity similar in bodily form (maybe in the sanctuary of the second of these temples, though I have no photo nor do I remember which chapel).
Porter & Moss (1994) Topographical Bibliography, II Theban Temples , 192 – 194 & plans VI & XVI