Talking is probably about the only thing they can do, other than try and annoy it to death; Apollo will try and talk regardless, because that's how he rolls. The slight issue is one I'll need to poke the mods about; unknown to him, Apollo's the reincarnation of a Pokémon who actively betrayed the gods and took Union's side to fight them. If Heatran knew him in his past life and recognizes him through his mental "voice" it might not be happy, to say the least.