Croconaw's Jaw Clamp attack says "Until the end of your opponent's next turn, as long as Croconaw is your Active Pokémon, the Defending Pokémon can't retreat, and if the effect of an attack, Pokémon Power, or Trainer card would change that player's Active Pokémon, that part of the effect does nothing."
In the original Compendium there's a ruling that explicitly states that Jaw Clamp's effect prevents the effect of Scoop Up (Base Set 78), so unless that has been overruled we know the effect does not just block switching effects.
Question 1: Let's say Croconaw attacks, for example, Lumineon V (Brilliant Stars 40), and then Lumineon V uses its Aqua Return attack, which says "Shuffle this Pokémon and all attached cards into your deck.". I'm assuming Aqua Return's damage is dealt normally, and that Lumineon V is not shuffled into the deck because of Jaw Clamp's effect. What happens to the cards attached to Lumineon V? Similar questions can be asked with attack texts like "Return this Pokémon and all cards attached to it to your hand" and "Discard this Pokémon and all cards attached to it."
Question 2: Are evolving and devolving the Active Pokémon considered ways to change that Pokémon? If so, I imagine Jaw Clamp's effect would prevent the effects of cards like Hyper Devolution Spray (Neo Discovery 73), Undersea Ruins (Aquapolis 138) and Pokémon Breeder (Base Set 76) when those cards target the Active Pokémon
In the original Compendium there's a ruling that explicitly states that Jaw Clamp's effect prevents the effect of Scoop Up (Base Set 78), so unless that has been overruled we know the effect does not just block switching effects.
Question 1: Let's say Croconaw attacks, for example, Lumineon V (Brilliant Stars 40), and then Lumineon V uses its Aqua Return attack, which says "Shuffle this Pokémon and all attached cards into your deck.". I'm assuming Aqua Return's damage is dealt normally, and that Lumineon V is not shuffled into the deck because of Jaw Clamp's effect. What happens to the cards attached to Lumineon V? Similar questions can be asked with attack texts like "Return this Pokémon and all cards attached to it to your hand" and "Discard this Pokémon and all cards attached to it."
Question 2: Are evolving and devolving the Active Pokémon considered ways to change that Pokémon? If so, I imagine Jaw Clamp's effect would prevent the effects of cards like Hyper Devolution Spray (Neo Discovery 73), Undersea Ruins (Aquapolis 138) and Pokémon Breeder (Base Set 76) when those cards target the Active Pokémon
