Twineedle inflicts damage, hitting the target twice per use. The second strike has a 20% chance of poisoning the target, unless the target is Poison-type. Although only the first strike can be a critical hit, the second one will deal the same amount of damage.
Twineedle will end immediately if the first strike breaks a substitute. Bide and Counter will only acknowledge the second strike of this move.
Each strike now does damage independently, and either of them can be a critical hit.
Twineedle will now hit again if the first strike breaks a substitute. If the first strike breaks a substitute, the second strike can poison the target.
If the user is holding a King's Rock, the final strike has a chance to cause the target to flinch.
Twineedle can no longer poison Steel-type Pokémon.
Twineedle is no longer able to cause the target to flinch if the user is holding a King's Rock.
Both of Twineedle's strikes now have an independent 20% chance of poisoning the target.
Generation V onwards
If the first strike activates the target's Focus Sash, Focus Band, or Sturdy, the second one will cause the defending Pokémon to faint. A Focus Band can still activate again to prevent fainting, but this chance is independent of the previous one.
If the target has Weak Armor, each strike will activate it.
Table assumes the user is in the square marked by > facing to the right. Orange squares indicate spaces that are hit. Red squares indicate the knockback on hit Pokémon. A blue square indicates the user's position after performing the move.
Power = 26 | Accuracy = 100% | Effect = Hits twice and has a 20% chance of poisoning each target with each hit.