Does poking yourself with a needle with the intent to do damage require the Attack action, or can it be done as a (free) object interaction?

Question

Does poking yourself with a needle hard enough to cause damage require the Attack action, or can it be done as a free object interaction?

This task is certainly no more involved than opening a door, which is the example of an object interaction in the PHB. Also, having your player do an Attack roll for such a trivial thing feels ridiculous. However, this would provide an easy way for Barbarians to sustain their rage when they cannot attack or are not attacked, which might be seen as game-breaking.

Answer 1

RAW: A self-attack requires the Attack action

Starting with the Other Activity on Your Turn section, we are told what sorts of activities we can take for free. I've excluded the irrelevant parts:

Other Activity on Your Turn

Your turn can include a variety of flourishes that require neither your action nor your move.

...

You can also interact with one object or feature of the environment for free, during either your move or your action. For example, you could open a door during your move as you stride toward a foe, or you could draw your weapon as part of the same action you use to attack.

...

The DM might require you to use an action for any of these activities when it needs special care or when it presents an unusual obstacle. For instance, the DM could reasonably expect you to use an action to open a stuck door or turn a crank to lower a drawbridge.

None of the descriptions offered here provide anything about doing damage to an object or creature, so at best it's something the DM would require an action for. So lets jump to the Use an Object section of actions to see if there's any type of interaction with an object that can do damage:

Use an Object

You normally interact with an object while doing something else, such as when you draw a sword as part of an attack. When an object requires your action for its use, you take the Use an Object action. This action is also useful when you want to interact with more than one object on your turn.

IMPROVISING AN ACTION

Your character can do things not covered by the actions in this section, such as breaking down doors, intimidating enemies, sensing weaknesses in magical defenses, or calling for a parley with a foe. The only limits to the actions you can attempt are your imagination and your character’s ability scores. See the descriptions of the ability scores in the Using Ability Scores section for inspiration as you improvise.

When you describe an action not detailed elsewhere in the rules, the DM tells you whether that action is possible and what kind of roll you need to make, if any, to determine success or failure.

Again, nothing here that immediately stands out except for breaking down a door, but typically that runs as a skill check, and not something that targets hp. The only other part that seems relevant is "When you describe an action not detailed elsewhere in the rules...". So since there are rules for doing damage under attacks, lets see if this type of activity is covered under the Attack action:

Attack

The most common action to take in combat is the Attack action, whether you are swinging a sword, firing an arrow from a bow, or brawling with your fists.

With this action, you make one melee or ranged attack. See the "Making an Attack" section for the rules that govern attacks.

So this sends us down to the Making an Attack rules:

Making an Attack

Whether you're striking with a melee weapon, firing a weapon at range, or making an attack roll as part of a spell, an attack has a simple structure.

1. Choose a target. Pick a target within your attack's range: a creature, an object, or a location.

2. Determine modifiers. The DM determines whether the target has cover and whether you have advantage or disadvantage against the target. In addition, spells, special abilities, and other effects can apply penalties or bonuses to your attack roll.

3. Resolve the attack. You make the attack roll. On a hit, you roll damage, unless the particular attack has rules that specify otherwise. Some attacks cause special effects in addition to or instead of damage.

If there's ever any question whether something you're doing counts as an attack, the rule is simple: if you're making an attack roll, you're making an attack.

Based on the rules laid out here, it seems that this best qualifies as an Attack action, since you are making a damaging attack against a creature in range (yourself). The other interactions don't cover this kind of activity, but this specifically does.

As to whether or not this would/should require an attack, there are other questions that discuss that.

Could it even sustain a barbarian's Rage anyways?

As NautArch pointed out in the related question he linked, a barbarian's Rage feature says:

It ends early if you are knocked unconscious or if your turn ends and you haven't attacked a hostile creature since your last turn or taken damage since then.

Hostile is the key word here. To be hostile the creature must be opposed or antagonistic to your goals (English definition). Because you are inherently aligned to your own goals and objectives, by definition you cannot be hostile to yourself. Thus, the action of self attacking would not qualify for fueling rage, though any damage done would.

Answer 2

You can poke yourself with a needle without attacking but it won't do hit point damage.

Hit points are an abstraction designed for combat, and represent getting worn down by enemy attacks. They don't represent bodily injury as such. The average human has four hit points and yet can survive childbirth. A 10th-level fighter with 100 hit points still can't survive decapitation.

You really shouldn't be accounting for hit point damage unless it's from attacks (or harmful spells or traps or a very few other sources). If you jab yourself with a needle then there's now a needle stuck in you.

If this worked, then everyone would do it, and maybe they do.

There's a whole class of zero-risk, zero-cost obvious tricks that some players will say they're doing and expect to get rewarded for. "As we walk through the woods I stay alert for an ambush," "I exhale and then hold my breath before releasing an arrow," "I keep a sharp rock in my boot so that I can stomp on it to stimulate my barbarian rage," etc.

Since these tricks are obvious and have no downside, it's reasonable to assume that everyone's already doing them when it would be useful, and whatever effects they have are baked into the mechanics. Of course you're trying not to get ambushed, so roll initiative to see if you succeed. Yes, your character knows how they're supposed to breathe when shooting, that's why they get that +2 for proficiency.

It is highly unlikely that you, personally, know more about being in an adrenaline-fueled murderous frenzy than your D&D character does. If trivial self-injury was at all useful to that, then we'd expect barbarians to have figured this out, and to wear gear that exposes lots of skin and has random sharp points everywhere to slash themselves open on. And they'd be covered in scars. And hey, many of them look exactly like that, so maybe there is some deliberate self-injury going on as part of their battle-psyching-up process. But they're still required to attack an enemy or take a hit to sustain their rage.

Answer 3

I would say 'no' ... but there are other arguments that I would consider.

First of all, I would say 'no' since I am 100% convinced that I'm able to draw blood on myself with a needle without fail every time. That seems logical but D&D is not always logical so in my opinion we need to look at this from both a logical and illogical point of view.

So as a DM I would rule that the "self attack roll" is not necessary, but taking an action for it would be. But that's my own subjective take on it.

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I'm going to go further into the analysis of this question, since your question brings to my mind the following thought (which, I'm sure, is also the reason why you are asking this one):

Should a barbarian be able to maintain his Rage indefinitely using such a simple workaround?

So, technically (RAW) a barbarian's Rage is something that keep going as long as the characters attacks an opponent or receives damage. Hitting themselves with a needle to keep the rage going would work if we consider than there's nothing more to consider than 'how the rules are written and applied mecanically'.

But if we shy away from purely interpreting the rules as written, we can ask ourselves "Why exactly would a barbarian be enraged by the fact that he is attacking or being damaged ?". Is it simply the pain or the adrenaline of the fight ? The sight of blood ? Or is there possibly more to explain why they would be enraged and how they would remain in that state. Doesn't it feel weird that a character punching himself would be enraged by self harm ? Wouldn't it make more sense that it is in fact the origin (of the damage taken) or the target (of the barbarian's attack) that would cause them to be enraged ?

I don't have an answer here, just a line of thought. I figure this is very subjective and each and every group or player could decide to go one way or another.

But I remember in previous editions and other systems (Pathfinder), when a barbarian's Rage was something dangerous for the group if the barbarian was still raging when there were no ennemies, he had no way to stop it sooner and would end up chasing and hitting his allies, blinded by his rage and to me, wanting to keep that rage going simply for the "mechanical benefits" seems detrimental to the flavor of barbarian rage.

Answer 4

Poking yourself isn't an attack

Poking yourself with a needle and the effects thereof are not covered by the rules. You can make a reasonable guess about how it would work, but you will need your DM to sign off.

Q1: Is poking yourself with a needle an attack?

An attack is an aggressive and violent action against a target which can or will defend themselves. Poking yourself with a needle is not an attack. You do not need to take the attack action, nor roll an attack, nor roll damage.

Q2: Can you poke yourself as a free object interaction?

Maybe. If you wanted to do it in a controlled manner to only deal 1 point of damage, that would probably be an action. If you wanted to haphazardly stab yourself dealing an uncertain amount of damage, that would probably be free.

Q3: Can you poke yourself to sustain Barbarian rage?

So long as you take damage, yes.