Glitch

A glitch is an flaw/unintended effect within a game. RuneScape have seen many glitches, and here is a page where it documents them.

Knife Glitch
The Knife Glitch occurred in 2002 in which a player was able to equip multiple knives and gain an enormous attack bonus. This would be done by dropping a Steel Scimitar and repeatedly clicking on any knife among a full inventory of them. Jagex took action against any abusers by banning Player killers and temporarily banning any skillers.

Great Party Hat Dupe
The greatest glitch in RuneScape History, this was the result of an attempt to trade a Scythe through the use of a third-party program called Auto-Rune. Although it failed, it was discovered that any non-stackable item could be created, and so, the most expensive item, the Party Hat, was duped until the glitch was leaked and patched.

Auto-Rune Gltches
With the use of Auto-Rune, not only were items duped, but people could also:
 * Attack and kill themselves in the Wilderness
 * Make themselves invisible at the Make over mage
 * Attack any NPC
 * Cast Spells without Runes or Target

Fatigue Glitch
A flaw during server maintanence caused all Beds and Sleeping Bags to not work in all non=veteran servers. It was fixed shortly before the second reopening.

Infinite Zombie Spawn
Normally, a Necromancer would only spawn 7 zombies. But if a player kills the second Necromancer without killing the spaws, then the first Necromancer will be able to summon 7 more until the player stops doing so.

Crash Bug
An old flaw in which if a NPC is examined after death, the game crashes.

She-Male Bug
There are several versions of this bug. The first was to equip a Rune Plate Mail Body as a bearded man, then change the item into a Rune Plate Mail top. The second was through the use of Auto-Rune. Lastly, it can also be made by

Death Bug
The death bug is a humorous, but sadly useless glitch in which a player dies from poison while interacting with an NPC/Object. If timed correctly, the player would die and the options to continou an interaction/conversation would persist. Known effects include:
 * Forced teleportation
 * Bank in wrong location
 * Complete Quests in wrong locations
 * Store interface at wrong location

Gnome Ball Smuggle
A oversight in which Gnomeballs could be taken out of the minigame. Methods include:
 * Tele-Grab
 * Teleport
 * Shoot