What are the mechanics for hiding something that is not yourself?

Question

How can a cleric hide a living body? asked for cleric spells that would keep the body of an unconscious but live comrade unseen.

I considered Pass without Trace, since it targets creatures with no requirement that the creatures be conscious, but then realized that if the companion was unconscious, it could not make a Stealth check, so a +10 bonus to no roll is still no roll.

That got me thinking of the larger issue of hiding things that don't get their own checks. Hiding a conscious character (as in preparing an ambush) would be the Help action, providing advantage on the other character's Stealth roll. But what would you do to represent a character trying to hide something that didn't get its own rolls?

1. Is there an established mechanism for this? (I haven't found any). Looking for something would be a Perception or Investigation, but what would this be contested against?

2. I am thinking this would be a Survival check, possibly Sleight of Hand for anything small enough to fit in one hand but that might presuppose active observation while trying to hide it. Thoughts?

3. What sort of conditions would be sufficient for giving the character hiding something a circumstances bonus (advantage)? One would be abundant time...so how long?

Answer 1

Sleight of Hand is usually the relevant skill, but different situations may require the DM to rule otherwise.

From the Player's Handbook:

Sleight of Hand

Whenever you attempt an act of legerdemain or manual trickery, such as planting something on someone else or concealing an object on your person, make a Dexterity (Sleight of Hand) check. The DM might also call for a Dexterity (Sleight of Hand) check to determine whether you can lift a coin purse off another person or slip something out of another person's pocket.

Sleight of hand is going to be the relevant skill whenever you are trying to conceal something while being observed. If there is a chance of being caught while performing the action, use sleight of hand. Note, sleight of hand is usually going to be for something small, its sleight of hand, not sleight of arms.

In situations where sleight of hand maybe does not fit, such as trying to hide something while not being observed, a DM could consider an Intelligence (Stealth) check:

Intelligence Checks

An Intelligence check comes into play when you need to draw on logic, education, memory, or deductive reasoning. The Arcana, History, Investigation, Nature, and Religion skills reflect aptitude in certain kinds of Intelligence checks.

If we have some time to ourselves to hide something like a large object in a room, I would rule that such a task requires logic and deduction to determine what makes a good hiding spot for the object. I would call for an Intelligence based stealth check, Intelligence (Stealth), since logic and deduction, as well as knowledge of stealth, come into play.

Other situations may better fit alternative ability checks, its really up to the DM. Conceivably, if we were trying to conceal a body in forest, a Wisdom (Stealth) check may be appropriate - the PHB says about Wisdom Checks:

Wisdom Checks

A Wisdom check might reflect an effort to read body language, understand someone’s feelings, notice things about the environment, or care for an injured person.

Recognizing good hiding places for a body in the natural environment seems to be reflected in this description of wisdom checks.

Answer 2

It's an ability check

First we decide if the action is best dealt with via an ability check, saving throw, or attack roll. In this case it's obviously not an attack or save, so it's an ability check.

Using Dexterity

Each ability check corresponds to one of the six abilities. Of those abilities, Dexterity is used for being physically sneaky, agile, or otherwise rogue-like, like when rolling to hide or use thieves' tools or solve complicated puzzle-locks via contortionist stuff.

Charisma is used when doing other rogue-like stuff like lying or disguising or forging documents, but if this is more about physical hiding it's not part of that secondary sneakiness attribute.

to which a character's proficiency bonus may apply

You get proficiency if you have a/the relevant skill. Here, you've already decided that's stealth. You also get proficiency if you employ a tool you are proficient in as part of the check, or use background proficiencies and the DM rules it makes sense.

Which is opposed by either Wisdom(perception) or Intelligence(investigation)

It might seem like a saving throw could also work, but physically hide-y ability checks are always opposed by Wisdom(perception) or Intelligence(investigation).