This question is inspired by: Is future technology that is indistinguishable from magic considered a "Magical Effect"?.

Darkness spells and magical effects block all (non-magical) light. A laser is coherent light. What would happen to a laser beam entering an area of darkness? Would the effect depend on how much energy is pumped into the laser beam?

It seems likely to me that darkness wins out. But a laser can cut hard metals and hard minerals, so it has more energy within its beam than sunlight in an equivalent volume / beam cross-section.

  • 12
    \$\begingroup\$ I feel like there's an "I attack the darkness" joke somewhere in here.... \$\endgroup\$ Commented Oct 30, 2018 at 18:55
  • \$\begingroup\$ Related: Does Darkness cast a shadow? \$\endgroup\$ Commented Oct 31, 2018 at 13:32
  • \$\begingroup\$ I've often wondered why Darkness doesn't impact Radiant damage, since Silence completely negates Thunder damage. :) \$\endgroup\$
    – Taxi4Dave
    Commented Oct 16, 2019 at 20:45
  • \$\begingroup\$ @Taxi4Dave: Good point. Darkness ought to negate Radiant damage due to visible and possibly near-visible IR & UV damage. \$\endgroup\$ Commented Oct 17, 2019 at 15:10

1 Answer 1


It would disappear from sight when it enters the darkness but function exactly the same otherwise

Darkness says:

A creature with darkvision can't see through this darkness, and nonmagical light can't illuminate it.

Laser beams from a laser gun from the DMG are not a magical source. Thus the laser beam is also not magical. Since it is not magical it will be unable to illuminate the area covered by darkness.1

However, the spell only says that it is unable to illuminate the darkness, not that the laser ceases to exist. So, the laser beam would function otherwise like normal in the darkened area (eg it would hit and damage targets) and if it didn't hit something would come out the other side of the area the same as it went in (eg bright and lasery). The same thing would apply to, for example, a flaming arrow.

The power level of the light source doesn't matter at all - only the power source. You could place something with the illumination power of the sun itself in the center of the darkness and it wouldn't shine at all unless it was a magical light source.

1 - Obviously if this is using some sort of custom setting/item created by a DM which they do define laser shooting technology as magical, then the laser bolt would illuminate the darkness. However, by default the rules do not indicate that laser guns are considered to be magical at all.

  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$
    – mxyzplk
    Commented Oct 31, 2018 at 1:42
  • 1
    \$\begingroup\$ This would create weird complications where you could see through darkness allowing you to see the silhouette of everything within the darkness given that the other side of was bright light. If the darkness spell was cast in an area surrounded by bright light then you could see pretty much exactly where your enemy was within because of that silhouette. \$\endgroup\$
    – Dezvul
    Commented Dec 16, 2019 at 11:24

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