Well, grumpy ... I'm almost assured it will be in the last place you look!
How about folded inside whatever fabric you had wanted to use it with in the first place? I sometimes fold the pattern with the fabric so I don't forget what I wanted to use it for.
You do realize of course your fuzzy butts are enjoying you looking all over the place, muttering about where it could be, bending, stretching, digging around....at least I'm sure they are amused.
Good luck to ya