if I'm hanging upside down and get knocked out, do I fall, or stay stuck to the ceiling?

When you're knocked out, you are subject to the unconscious condition. This states that you fall prone. My ruling as DM would be that you would then fall from the ceiling, especially since you are no longer able to actively use the slippers, and gravity is still a thing.

I'm sure it's been answered somewhat officially somewhere as well, but I'm not in a position to look that up right now. 

I don't think that's the case. There's nothing that requires any effort on the user for the slippers to work, they simply stick to surfaces. if you can hang upside down while conscious and dangling, there's nothing that says just because you are no long conscious that the item just all of a sudden stops working. Ring of protection continues to give you a +1 save when you make death saves whilst unconscious. I don't see why these would be any different.

The problem with the reasoning is you would never be able to lift your feet from the floor or jump. So you would have to be activating at least subconsciously. Therefore if you lose Consciousness you fall.

 My question is do they have a weight limit? I have a turtle monk that wants them and he weighs 450 lbs plus his gear. There's nothing that says he can't but I'm having a hard time justifying it.

I don't think they have a limit at least to the weight of the attuned wearer.they just work unless slippery surface. torn between these and boots of elvenkind as an infusion for my artificer. I like the idea of fire artillery on the shoulder as I spider climb slipper up the castle walls and cast the web spell.

These slippers defined the way I played my rogue/barbarian, they were so fun for me.

The magic tied to the slippers requires you to focus on it, so they stop working when you go unconscious.. 

I think it would be funnier to let em hang like a human pinata get poked by the bad guys

Be careful of casters with the Grease spell while you're hanging out on ceilings. 

What do you mean by "focus," and where does it say you need that?

I believe a character would fall from the surface.

For the Long Jump rules, it states:
When you land in difficult terrain, you must succeed on a DC 10 Dexterity (Acrobatics) check to land on your feet. Otherwise, you land prone.

This rule shows that being prone is not the same as being on one's feet.

The unconscious rules state:
The creature drops whatever it's holding and falls prone.

So, when a character goes unconscious they would go prone, which means they are not on their feet, and since these are slippers, they would not work. Additionally, specifically stated in this item is it leaves your hands free, lending to the reasoning that you must use your feet/slippers for climbing.

As a counterpoint, one may argue that since you were standing on the surface with the slippers, falling unconscious would not remove the magical properties of an attuned item (see Attunement in Chapter 7) then the slippers would keep their properties and have you dangle there, but you would definitely still drop anything you are holding.

TL:DR: Ask what your DM thinks.

I’m trying to pick random magic items to describe as daelkyr creations so I’m better at that if I ever get to run an Eberron campaign. In this case, it’s a symbiont.

“Valaara, the Crawling Queen, has bred these bizarre beetles over the course of centuries, and has finally perfected its craft. Place the beetles atop your feet for the duration of attunement. They will chew and burrow down to your soles, from which their legs then protrude, as your feet rapidly heal. The beetles’ legs will protrude through any footwear. While the beetles are present, you can move up, down, and across vertical surfaces and upside down along ceilings, while leaving your hands free. You have a climbing speed equal to your walking speed. However, the beetles don't allow you to move this way on a slippery surface, such as one covered by ice or oil.

Symbiotic Nature. The beetles can’t be removed from you while you’re attuned to it, and you can’t voluntarily end your attunement to them. If you’re targeted by a spell that ends a curse, your attunement ends, and beetles crawl from your skin all across your body until they’re out of your system”

Just asking, per the description above it does not state concentration or focus, so is it listed elsewhere and if so can you please provide the link. 

Thank you

im having a hard time finding a cost on these does anyone know where i can find that?

I like the idea of someone using these to walk up to the ceiling and sleep upside down like a bat. When you sleep you go unconscious so for that to work you would stick. My interpretation is that you dont need focus or consciously stick. You can stick and unstick at will just like taking steps each step up a wall would require you to unstick one of your feet and stick em back I dont think that would be a conscious/focus requiring activity

Quote from 77_77_77 >>

I like the idea of someone using these to walk up to the ceiling and sleep upside down like a bat. When you sleep you go unconscious so for that to work you would stick. My interpretation is that you dont need focus or consciously stick. You can stick and unstick at will just like taking steps each step up a wall would require you to unstick one of your feet and stick em back I dont think that would be a conscious/focus requiring activity

 Just as an FYI, no one should do that. Spending more than a few minutes inverted is a good way to seriously hurt or kill yourself in extreme situations. The humanoid body was not designed like a bat's. Our circulatory systems will be seriously compromised. Prolonged inversion can cause blood vessels to rupture in the brain, your heart to fail or asphyxiation. 

Quote from BobbyBrewer45429 >>

im having a hard time finding a cost on these does anyone know where i can find that?

 DMG page 135 gives a chart on the value of magic items based on rarity. Slippers of Spider Climbing are Uncommon. So if you found someone selling these you could expect the cost to be between 101 and 500 gold pieces.

Those absolutely look like Crocs lol 🤣

How would these work if one of the boots got knocked off, or if you could only put one of the boots on (like if you had one leg)?