Guild Wars 2

Using the Guardian GS#5 skill(Blinding Blade) on a tentacle right before it dies will result in the tentacle dropping multiple crystals.

Using this bug definitely removes the possibility of a crystal shortage. Abusing this bug allows you to kill Jade Maw before phase 3, because each tentacle will drop ~10 crystals. Killing Jade Maw before phase 3 does not glitch the fractal, but you will still have to kill the rest of the Jade Colossus to complete the fractal. The only difference is that you get to skip phase 3.

I consider the phases of the fight to be:
Phase 1: Starting phase, 2 tentacles up and a bunch of trash mobs.
Phase 2: 4 tentacles that do not respawn and multiple Jade Colossus
Phase 3: 6 tentacles that respawn until the boss is dead.

Here’s the breakdown:

Normal:
Team DPS’s a tentacle down to 0 hp.
Tentacle loses all debuffs and becomes invulnerable.
Tentacle drops a single crystal.
Tentacle disappears.

Buggy:
Team DPS’s a tentacle down to low hp.
Guardian uses GS #5 skill and puts the “debuff” on the tentacle.
Team brings tentacle to 0 hp.
Tentacle becomes invulnerable loses all debuffs EXCEPT the guardian GS#5 debuff.
Tentacle is stuck in a “loop” and drops crystal after crystal until the debuff wears off.
Tentacle disappears.

The bug is actually kind of neat. A guardian can “make it rain” crystals, which leads to a lot of “lol’s” “omg’s” and “wtf’s” in party chat.