No, it's not an April Fool's joke. It's, um, a rarity in the world of Twilight Zone collectibles: this one is designed exclusively for the ladies. I give you.... The Invaders thong.
Wanna order one for that special lady in your life? Go here. The Invader is a bit hard to see in that somewhat-garish design, but if you encountered this particular item in the wild... well, the design probably wouldn't be foremost on your mind. If you follow the above link, you'll note that the exact same design is available on a wide variety of items (T-shirts, mugs, chef's aprons, men's boxers, etc), but none are quite as charming or alluring as the thong. I'm tempted to get one to pair up with my Hallmark Valentine's Day card which, coincidentally enough, features an Invader on the back holding a box of chocolates. Ah, romance.
... on a side note, I love The Invader. The character, I mean. The episode... well, not so much. I appreciate the atmosphere and the production value (and the tour-de-force performance by Agnes Moorehead, of course), but I've never found the episode particularly effective. Anyway, I love the little guy, and I've decided that he's going to be my next tattoo. I'm using the following picture of the glorious Sideshow Collectibles Invader figure (which I don't own.... yet) as a reference shot for the tattoo artist. In other words, it's gonna look pretty much just like this (same angle, etc):