Grid bugs are the annoying gnats from Nethack. They are creatures of lightning, who shock you over and over with tiny bites. They are the simplest of all monster. Grid bugs tend to be on the first few levels, and have never been seen to leave a corpse. The grid bug death is considered a shameful defeat.

The grid bug has no magic resistance, a speed of 12 (about average) and a AC of 9. They are usually able to be killed in one connecting attack, or one magic spell. They are almost never a formidable foe.

The grid bug is a Nethack monster taken from the Tron mythos (and the only one at that). While not mentioned in the movie there is a bit of mentioning it from the novel form:
Tron looked to his mate and pilot. "I'm going to check on the beam connection, Yori. You two can keep a watch out for grid bugs." Tron paced forward along the slender catwalk that still seemed awfully insubstantial to Flynn, though he knew it to be amazingly sturdy. He gazed after Tron, asking himself what in the world a grid bug was, and hoping that the beam connection -- to which he'd given no thought whatsoever until this moment -- was healthy and sound."
Within the game, a grid bug is:
    MON("grid bug", S_XAN,
        LVL(0, 12, 9, 0, 0), (G_GENO|G_SGROUP|G_NOCORPSE|3),
        A(ATTK(AT_BITE, AD_ELEC, 1, 1),
        SIZ(15, 10, 0, MS_BUZZ, MZ_TINY), MR_ELEC|MR_POISON, 0,

For those of you who don't read source that often:

  • Common name: grid bug
  • Symbol: Xan (a lower case 'x')
  • Level 0, speed 12 (range 1-36 where a normal human has a speed of 10), AC 9, Magic Resistance 0%
  • Genocidable, appears in small groups, leaves no corpse
  • Neutral alignment
  • Attack is a bite - electrical that does 1d1 damage
  • The corpse is defined as 'weight 15' and 'nutrition 10' - though that has very little bearing on the game (they don't leave corpses).
  • Makes a buzzing sound (when you chat with one)
  • Is tiny (cannot kick, not a good anchor when grappled, cannot open doors, cannot wear armor or weapons, or ride a steed) - however, the very small do ignore boulders.
  • Resistant to electrical attacks and poison
  • An animal (as opposed to demon or some such)
  • Hostile
  • does not show up in the infrared
  • magenta color

The source has a bit more to say about the grid bug, though it is more along the lines of what they can and cannot do - most notably, a grid bug can only move in cardinal directions (North, East, South, West) and cannot move along the diagonals. Neither can a grid bug attack at an angle. This makes it paticularly easy to avoid a grid bug making death (even for an armorless and weaponless tourist) rather embarrassing. In dealing with shopkeepers, there is a test that makes certain that the shopkeeper does not become angry for a grid bug zapping it.

You turn into a grid bug!--More--
You become much too small for your shirt!--More--
You find you must drop your weapon!--More--
You can't even move a handspan with this load!
Being polymorphed into a grid bug gives you shock resistance and poison resistance, though its not that useful as one can see above. Furthermore, like the moster, when polymorphed into a grid bug one may not move along the diagonals. The player polymorphed into a grid bug has about the following stats:
Dlvl:1  $:842 HP:4(4) Pw:2(2) AC:9  HD:0 Overloaded
While a gridbug, you are constrained by the save movement rules as the monster is - not able to move in diagonals.


  • They say that a grid bug won't hit you when you cross it.
  • They say that a grid bug won't pay a shopkeeper for zapping you in a shop.
  • They say that grid bugs only exist in a strictly Cartesian sense.

Demonic malediction

  • "Wait! I shall polymorph into a grid bug to give thee a fighting chance!"

All information gleaned from reading the sources to Nethack.

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