I actually used the arm as part of build for a custom cyberweapon for Sara in my game. I'm a huge fan of Hardwired, the classic cyberpunk novel, and had to build a cybersnake with a Shadowrun twist for my blatant knock-off of the former hooker turned street samurai from the book (didn't even bother to change her name). I ended up with a mix of an Oral Slasher from Augmentation (1500), the articulated weapon arm from augmentation (5,000), a cybereye with thermographic vision (1,250), and a Monowire Whip (3,000). Came up with a pretty nasty piece of work that is basically an implanted telescoping monowire rotorooter.
Cybersnake 0.5 Essence Damage: 6P AP: -3 Availability: Be Coo-Coo for Cocoa Puffs enough to want one in your character and impress your GM with a backstory...and pay 10,750
The cybersnake requires the Exotic Weapon: Cybersnake for use.
Consisting of an articulated tube of artificial muscle and cartilage that can extend almost the full meter, a cyberware heat sensor, and a collapsible monowire "flower" at the end, this fearsome (and completely bugfuck crazy) cyberweapon hides inside of a bodily orifice before extending to strike. It can attack in melee combat as an add-on attack to armed and unarmed combat with a reach of 0. It can also be used to eviscerate when the user is in, shall we say "friendly" ranges where the cybersnake can enter the body of the victim and use the heat sensor to start ripping the living hell out of the largest heat sources it can find, invariably the major blood-bearing organs. The user can use a lubricant to keep blood and bits from sticking to the cybersnake as well allowing it to slide freely in and out of the internal bioware "sheath". As a side note, if the orifice chosen is the mouth, the user will be forced to hold their breath while the cybersnake is extended.
So basically, you're frenching with this hotty (in the PG rated version of this scenario) when this meter-long monowire roto-rooter hops out of their mouth, down your throat, and starts making chunky salsa of your important bits without any immediate external indication that your guts are mush when they're walking past your guards on the way out.