Appears to be an owl chick- most likely why the poor thing hasn't moved in a couple days.
Looks like he's fallen out of the nest and hasn't been able to get back up.
Try and have a look around the area in which you found him to see if you can find the hollow he might have come from- if you do find it (and the parents are still hanging around), pop him back in there when they're out and they'll go straight back to looking after him with any luck. Owls don't have a sense of smell, so don't worry about your scent 'contaminating' him.
If you can't find the hollow, call your local council, the RSPCA or WIRES to have him taken away for specialist care ASAP.
For now, keep him in a warm, dark, quiet place so he doesn't stress.
Birds (and in particular young animals) are extremely prone to stress related issues.
I'm no expert in owls, but I believe chicks do NOT need water, and get all their moisture from their food.
An ideal diet would be day old chicks (chopped up) or small mice, but since the little guy has presumably not eaten since he's fallen out of his nest, I'd try and offer him bits of (raw) chicken if you have it.
Of course you'd either want to find the nest tonight, or call any of the three organisations mentioned above.
Remember, if you are in Australia (which I presume you would be), it is illegal to keep native wildlife without proper licensing.
Best of luck for the little guy.