"Have you seen my pet grasshopper anywhere?"

If you convey a fun, playful attitude this can actually work very well. If you convey the wrong attitude it can just come across as being strange and creepy.

If the girl responds with "oh yeah, I squished him with my foot, tease her about being a horrible person. If she asks what it looked like say something such as "well, he was about 1 inch tall, had the same hairstyle as you, was wearing a green cardigan". There are many threads this topic can lead to. Give it a try and let me know how it works for you!