This was already a WIP, actually! *feels bad*
But Emocezi has talked me into writing yours as well. No idea when It will be done as I have 44 WIPs on my plate right now. (I have a plot bunny problem) But I'm currently picking out names for Cougar's parents and plotting your idea out. I've never seen El Dorado, and I have an idea about how Cougar becomes Cougar, but other than that I'm following your prompt to the letter. \o/