Every Destiny player wants exotic weapons and armor, but because those items are so powerful, they're exceedingly rare. They're less rare in Destiny: The Taken King because it's possible to farm exotic engrams with very little effort, thanks to a new item in Xur's inventory.
Xur, the tentacle-faced weekend merchant, operates differently as of The Taken King's release. In addition to his usual slate of three exotic armor pieces — one per class — Xur now sells either an exotic weapon engram or an exotic armor engram. He also offers something called a Legacy Engram, which bears the same yellow color as an exotic engram but is guaranteed to turn into a Year One exotic; the engram is meant for players who want to fill out their collection.
Along with exotic engrams and gear, Xur always offers an assortment of items such as ammo syntheses. In The Taken King, he also sells a consumable called Three of Coins; a pack of five costs seven Strange Coins. Three of Coins increases the chance of an exotic drop the next time you kill a boss known as an "ultra." The effect stacks, although not in the usual way — your exotic chance won't quintuple if you pop five Threes of Coins at once. Instead, the way it works is that if you kill an ultra but don't get an exotic, the next Three of Coins you use will be more likely to produce an exotic drop upon killing another ultra.
An ultra, in Destiny, is a named enemy with a health bar that is entirely yellow and has a yellow skull next to it. You can find an ultra in Destiny's original campaign, at the end of the "Scourge of Winter" mission: Draksis, the Winter Kell. YouTube channel MeowzaForce Gaming highlights this specific boss fight as the best one for farming exotic engrams with Three of Coins, and that's because there's a checkpoint right outside the door. Plus, the difficulty of the activity doesn't matter here, so you can use this method on the default for "Scourge of Winter," a measly level 14.
Starting from the checkpoint, pop a Three of Coins and head into the Winter Kell's chamber. Hit him a few times with a sniper rifle to get his health low. Then equip a rocket launcher, walk up to him and fire a rocket from close range, killing him and yourself. Any loot he drops — like, say, an exotic engram or two — will still be there when you respawn at the checkpoint. From there, you can rinse and repeat as many times as you have Threes of Coins.
To be clear, the engrams won't necessarily be dropping like candy; a Reddit user who confirmed the technique said on the Destiny subreddit that he got three exotic chest armor engrams in a span of 15 Three of Coins uses. (Then again, you might see two drop at once.) But it's still a cheap and easy way to obtain exotic engrams, and either way, you're going to want to jump on this trick before Bungie inevitably patches it out.