OK. I've been unpacking all my kitchen stuff at our new house, and I came across something that I know I've never used; I can't even remember when/where I bought it; and, more importantly, I don't even know what it is!
It's a bright lime green silicone thing, sort of like a muffin tray. But it only has four holes, rather than 12. And each one is rectangular and pretty big - like 3-4" high. It sort of looks like it might be for making popsicles, but there's no top with sticks for it.
I'm baffled. And, yes, I know I have a problem with buying every kitchen gadget I see.

(I should have taken a picture, but I can do that tomorrow if nobody can identify it from my description!)