SDCC 20123 Toy Haul Report - Mystery Rock Edition!

Hey guys, check out this really cool rock I picked up...

OH MY GOD IT"S NOT A ROCK! AAARRRGGGHHH!!!

I actually have no idea what the hell this glorious thing is, but it was a dollar and I had to have it.

Any clues, gang? The copyright on the bottom says "CBS Toys 1985".