Where are you Shelly?

After feeding Shelly (he/she was given this name by my girlfriend) some leftover Morrisons finest Organic rhubarb yoghurt I left him/her gurgling on the plate and went to bed.

Imagine my horror this morning when I discovered Shelly had vanished. His/her plate had been sucked clean and he/she was nowhere to be seen. No sign of Shelly in the kitchen, or the lounge...how far can a snail travel in 8 hours?