What is being sexually attracted to all living being called?

Pansexual (gender-blind sexual attraction to all people)?

I heard someone describing a similarly priapic man, "He'd f*** a stonewall if he thought there was a snake in it!"

Pansexuality and omnisexuality might be words you could use.

I think I know him

But does that include attraction to moss, algae, the entirety of the mushroom kingdom, etc...? AKA being sexually attracted to all living being[s]?

I dont think there is a single term for that.
If they are sexually attracted to all humans and also animals, then that would be omnisexual or pansexual, paedophile (if including human children), and zoophile. If they are also attacted to objects and concepts that's objectum.

So I would use the terms onmisexual padeophile zoophile or if truly attracted to everything then omnisexual paedophile zoophile objectum.

Of course, zoophilia and paedophilia are illegal.

Exhausted.