[RPG] Does the Dungeon Delver feat still provide resistance to traps once they’re revealed

damage-resistancednd-5efeatstraps

As far as traps go, the Dungeon Delver feat provides these benefits (PHB, p. 166, 2nd and 3rd bullets) :

  • You have advantage on saving throws made to avoid or resist traps.
  • You have resistance to the damage dealt by traps.

Does the feat still give resistance to the trap's damage once they're revealed?

Here are a few specific cases:

  • An open spiked pit is found. Does the delver still get resistance to the trap if he knowingly tries to jump over it?
  • A Wall of fire is triggered from a Glyph of Warding spell. Does the delver still get resistance to the fire if, several seconds after the spell is triggered, he knowingly passes through the wall?

The source of the hesitation is the wording of the feat's description:

Alert to the hidden traps and secret doors found in many dungeons, you gain the following benefits […] (emphasis mine)

In other words, one might think that once a trap is revealed, and it's effects known, it's not a trap anymore, but a mere feature of the terrain, thus restraining the reach of the feat.

As a player, one would like to know so before choosing the feat; as a DM, another might want to know how to deal with delvers hurling themselves in harm's way saying: "Don't worry! That 60 foot deep pit was once meant as a trap… I should get only half of that falling damage!"

Best Answer

What is a trap?

It looks like the crux of your problem is that "trap" is hard to define, particularly with regards to knowledge and time.

After a bit of searching, I found only one location where a trap is actually defined. That's in the Find Traps spell on PHB 241:

A trap, for the purpose of this spell, includes anything that would inflict a sudden or unexpected effect you consider harmful or undesirable, which was specifically intended as such by its creator.

Of course, this is explicitly "for the purpose of [that] spell," so the utility is limited, but it's also the only place where a clear definition for a trap is given.

Based on this definition, a trap is either sudden or unexpected. This means that both of your examples are not traps. They are not sudden, because they have existed for long enough that the PCs can perceive them, and they are not unexpected, because the PCs are aware of them.

Also, if you were to extend the definition of a trap to anything that results from a trap, then this feat could potentially grant resistance to everything in an encounter. For example, a mimic is arguably a trap. Does a dungeon delver get resistance to the mimic throughout the entire fight?