While there is no direct ruling on Speed Slide, there is on the so-called "SWIFT" attacks, in which catagory Speed Slide belongs.
Q. Does Misty's Staryu's Swift hit through Scrunch? Transparency? How about Barrier?
A. It hits through ALL Pokémon Powers or attack effects or Weakness or Resistance. (August 17, 2000 WotC Chat Q69)
Q. When you use Misty's Staryu's Swift, do you still have to flip for Sand-attack?
A. Any effect that PREVENTS attacks must still be checked. Swift (if allowed to go off) basically ignores anything that tries to effect the amount of damage done. [Ed. Note: Sand-attack reads "If tails, this attack does nothing." This text can be interpreted as "If tails, the attack is prevented (including effects and damage)." Since Swift ONLY ignores effects that modify damage, one still needs to flip the coin for Sand-attack's effect.] (Aug 31, 2000 WotC Chat Q39)
Q. Would Misty's Stayu's (the one that does damage regardless of Weakness/Resistance/Pokémon Powers/effects of attack) do damage to a Raichu/Rapidsah/Seadra/Fearow/Blaine's Ponyta that got a heads on Agility? Cause Agility says prevent all effects of attacks, and the game text of the Staryu's attack IS an effect.
A. Yes it would still do damage, it ignores the effect from the Agility as stated on the card. (August 17, 2000 WotC Chat Q165)
Q. If base set Mewtwo used it's Barrier attack and if a pokemon used Swift, would Swift cause damage?
A. Yes it would. (Aug 9, 2001 WotC Chat, Q263)
Q. If I use the Swift attack and the opponent has a Metal Energy attached to the defending Pokémon, does the Metal Energy reduce the amount of damage or do the conditions of the Swift attack override the Metal Energy effect?
A. Swift will override the Metal energy card effect [on the opponent]. (Jan 18, 2001 WotC Chat, Q68b; Jan 25, 2001 WotC Chat, Q18)
Oh, I love Compendium.
