Chameleon, a gimmick by Blake Vogt, is a standard playing card that can attach to another and change, like magic.
Described by the creator himself:
Visually transform a card into the spectator's SIGNED card. Chameleon is a gimmick which attaches to any card in the deck. Once attached, it allows you to impossibly transform an indifferent court card into the spectator's selection. When you purchase this effect you will receive a handmade gimmick made by Blake himself that will last you for thousands of performances. You will also receive a download instructional teaching you a few of Blake's favorite color changes as well as a very clever routine where the spectator ends holding everything in their hands to examine. Purchase this insanely cool gimmick that can become any card... like a Chameleon.
If you're interested in more, you can check it out on Blake's shop here.
Where to buy?
I picked up this gimmick back in 2019 for $34.95, directly from Blake's online shop.
Unfortunately, the last time I checked Chameleon was out of stock. You can still check out the product page at Blake Vogt's Shop to make sure though. And, there's always eBay!