Sleeky Serpent is a boss you encounter at the top of the Evil Hideout. He was the one who received Crystal from Squelch. Crystal was supposed to know where the Dark Orb was, but wouldn't tell. She was then sent to the Order due to this fact. If you manage to defeat both Gatekeepers and touch both buttons on the same floor but different areas, you will unlock some treasure behind the two doors in the area where you fight Sleeky Serpent. MUCH later in the game, like when you get to the Gate to Hades, you will encounter Sleeky Serpent AGAIN (except his name is Serpent Neo.) This guy is much stronger than before. He is about level 70, (compared to the original Level 12 Sleeky Serpent is insane.) Serpent Neo gives 29,000 exp, and 2,400 gold, while Sleeky Serpent gives 800 exp and 500 gold. Sleeky Serpent has Poison Breath, while Serpent Neo has Fatal Breath, so watch out for that.