It's called Trespasser but this Destiny: Rise of Iron Exotic is supposed to be here.
Destiny updated earlier today in advance of next week's release of Destiny: Rise of Iron.
The patch did all sorts of things (you should check out the latest Destiny weapon rebalance, for one; there's a nasty surprise in there for King's Fall Hard Mode this week) but one of the little changes it made wasn't documented: one of the Exotics coming with Rise of Iron has slipped out early.
The weapon in question is Trespasser, an Exotic sidearm. Sidearms have been generally under-utilised in Destiny's combat sandbox, which is why Bungie buffed them in today's patch - so it could be well worth a look.
Destiny developer Bungie has acknowledged the drops so it doesn't look like an accident; I hope you've got some Three of Coins to burn.
Trespasser dropping early? Yup. Trespasser is dropping early. Have fun, Guardians!
— Bungie (@Bungie) September 9, 2016
Destiny: Rise of Iron is only coming to PS4 and Xbox One, which is why PS3 and Xbox 360 didn't get today's patch. You won't find Trespasser in the last-gen versions.
The expansion delivers a raid, new strike, crucible maps, overhauled Cosmodrome, new destination, loads of weapons and armour sets, another social space, more story missions, an ornament system and much more.