“Oh, I always liked that “phasing” ability, like the girl from the X-Men who could walk through walls and stuff,” the Doctor said idly. “I forget the comic book science of it, something about being able to pass her atoms in between the spaces between the atoms of whatever she was going through… but yeah, I just thought it would be fun to be able to walk through walls. Or just stick your head through and have a look. Oooh, that look like it hurt,” he added, as the girl finally got in a good shot and electrocuted the ice man.