Where's the Pikachu?

Just a short one. Because it is noteworthy.

The other day, while I waiting for my take-away in Pizza Hut, I heard "Pi-ka-chu?". If you didn't know, my message tone is Pikachu calling, "Pi-ka-pi, Pi-ka-chu?" But it wasn't from my Pikachu... whose Pikachu was it then? I didn't see any around... :P