Rulings - Pokémon Rulings Compendium

If an attack would KO a Pokemon, can you use Sitrus Berry to heal it first?: No. KO's have to be resolved before the end of the turn, and Sitrus Berry heals at the end of the turn after KO's have been evaluated.

Source: TPCi Rules Team (2020-02-06)

Can I use Sitrus Berry to heal damage received from Poison/Burn in between turns?: No, you cannot. Sitrus Berry only works at the end of a turn.

Source: TPCi Rules Team (2020-02-06)

Say I have Keldeo GX already in play, and my opponent uses Latios GX's "Clear Vision GX" attack with Power Plant in play. If I play a different Stadium to get rid of Power Plant, can I use Keldeo-GX's "Resolute Blade GX" attack now?: Yes, you can. When Power Plant is removed Keldeo GX's Pure Heart Ability turns back on, and Keldeo GX is no longer hit by the global effect of Clear Vision GX. If an attack does not place an effect on Keldeo GX directly, like an attack that puts an effect that isn't removed when returning to the Bench, it can be removed by reactivating Pure Heart.

Source: TPCi Rules Team (2020-02-06)

Say my opponent uses Trevenant & Dusknoir GX's "Pale Moon GX" attack on my Keldeo GX with "Pure Heart" while Power Plant stadium is in play. If I replace the Power Plant with another stadium during my next turn, does Keldeo GX get knocked out at the end of the turn or not?: If Keldeo GX remains the Active Pokemon it will be Knocked Out. Keldeo GX's Pure Heart Ability *prevents* effects, but it does not *remove* existing effects. If an attack like Pale Moon GX places an effect directly on Keldeo GX, that effect cannot be removed by reactivating Pure Heart; in other words, effects that are removed when returning to the Bench can't be removed by Pure Heart.

Source: TPCi Rules Team (2020-01-09), TPCi Rules Team (2020-02-06)

Does a player need to offer a cut when shuffling something other than their deck, such as when playing Marnie?: Yes. The purpose of a cut is to reduce the opportunity for cheating; that applies anytime a player is randomizing their cards.

Source: TPCi Rules Team (2020-02-06)

Can I use Hyper Potion to heal a Pokemon with less than 120 damage on it or if I have less than 2 Energy attached to it?: You have to heal at least 10 damage to play the card. You must also have at least 2 Energy attached to the Pokemon you're healing; if there are less than 2 Energy attached you cannot use this card.