skulk

Cheers! I have been wanting to make a similar deck ever since the Skulk mechanic became a thing. I don't think you really need Behind the Scenes, since you're already running so many creatures with Skulk. I would cut it in favor of Skeleton Key instead if you plan on running creatures without Skulk in this deck. Also, Pale Rider really only work well if you have cards with Madness in your deck, since you'll be able to cast them at reduced cost. Alms of the Vein is a pretty awesome Madness card I would suggest.

Also, I think you need to hone your strategy when it comes to your spells. You've got discard, removal, and Behind the Scenes going on. Although it's nice to have a deck that does a bit of everything, you should just pick one and focus on it so that everything works well together. I think discard and Skulk could be a great combo, since you'd be emptying your opponents hands and they couldn't even block your creatures if they wanted to. In my opinion you should stick to Skulk creatures that only have 1 power, since you'll be able to slowly chip away at your opponents life total that way. Also, why would you really need removal like Doom Blade when your opponent won't be able to (hopefully) block your Skulking creatures? You should definitely keep them, but maybe only in the sideboard? Just something to think about.

Lastly, don't forget about protecting yourself from removal. Think about this: How would this deck fair if you happened to run up against another swamp player running Go For the Throat? A plains player running Path to Exile? A mountain player running Lightning Bolt. A forest player running Prey Upon? An island player running any kind of counter spell?