The Trick Room glitch is a glitch in Pokémon Black and White and later games.
In order to activate this glitch, the user must boost their effective speed to more than 1808.
This can be done with any Pokémon with 302 or more in its Speed stat, holding a Choice Scarf and using Agility 3 times. The 4th use of the move will not increase your Speed, but it will attack first even under the effects of Trick Room, its effective Speed being 1812 (302 x 4 x 1.5). The easiest way to create this situation in Generation V is by getting an Old Amber from a worker in Twist Mountain, reviving it to get a level 25 Aerodactyl (aim for a +Speed nature) and leveling it up. Purchase the Choice Scarf from the Battle Subway for 48 BP.
Ever since Black and White, speed is computed as follows:
- Start with the raw speed stat, which will be between 4 and 504. (If the move Speed Swap, introduced in Generation VII, is used, it affects the underlying stats at this point but no later.)
- Apply stat boosts, between a x0.25 and x4 multiplier. Round down.
- Apply speed changes from other sources, such as Choice Scarf, Tailwind, or the Water Pledge/Grass Pledge swamp effect (but not paralysis). Don't round until you've made it through all applicable multipliers. After that, round to nearest, except that in case of a tie (an exact 0.5), round down.
- If the Pokémon is paralyzed, multiply its speed by 0.25 (Generations V-VI) or 0.5 (Generation VII and beyond). Round down.
- If the Pokémon's speed is greater than 10000, set it to 10000 as a hard cap.
- The speed at this point is locked in for the purpose of determining the power of the moves Gyro Ball and Electro Ball.
- If Trick Room is in effect, replace the speed with (10000 - speed).
- If the Pokémon's speed is greater than 8191, subtract 8192 from it.
The second overflow point in step 7 is normally extremely unlikely to be reached, only slightly less so than the first hard cap in step 5. But if Trick Room is in effect, the idea is that almost all Pokémon will be affected by that step and loop around without even trying. For example, under Trick Room, a speed stat of 100 becomes 9900 (looping back to 1708), while a stat of 400 becomes 9600 (looping back to 1408). However, a speed stat of 1809 in Trick Room inverts to 8191 and does not loop around, leaving it several thousand points faster than its counterparts with more usual ranges of speed.