Oh right, that reminds me.I forgot where I heard this, but Pikachu's thunder can pass through certain parts of Hyrule Temple.
Thunder will pass through all platforms within a certain distance below the cloud, or if the cloud begins inside an obstacle (like inside Hyrule Temple). This was made so that Pikachu's Thunder wouldn't be completely useless on stages with many platforms or hallways like Rainbow Cruise or Rumble Falls.
That reminds me again about a piece of game mechanics. All platforms, objects, and floors in Brawl are hollow. This probably doesn't mean much though outside of things like Pikachu's Thunder when the cloud spawns inside a stage object, or glitching yourself into stages occasionally.
Also, Twilight Prince, it's a picture of a girl dressed up as an Ekans, next to an actual Ekans.