The Peng Treasure is an item in Dead Space found in Chapter 11 of the campaign. The item itself represents a small golden statue of a woman. It is worth 30,000 store credits, but unlike most other items in the game, it is only obtainable once without glitching or hacking. Adding it to the player's inventory unlocks the achievement/trophy There's Always Peng!, which is worth 15 points on Xbox and a bronze Trophy on PlayStation.
It is unknown as to what the treasure actually represents, but it is quite possible that Peng is, or was, a sexual innuendo (or even possibly just a slang term) for erotic entertainment in the Dead Space universe. Many of the posters advertising Peng aboard the USG Ishimura contain risque interpretations of women. Several of the bathrooms on the ship contain graffiti tags enticing the player to call a number, claiming, "[they] give great Peng."
During the Dead Space 2 Thursday Night Throwdown, the games interface lead was asked "What is Peng?". While he didn't say what it is, he did say that it is something that may be revealed in the future, and hinted at it being more significant than what is currently assumed.
Obtaining the Treasure
Once in Chapter 11 (Alternate Solutions), the player must make their way to the hangar bay - this is also the first playable location outside of the ship. The treasure is located on the floor between the first and second walkways from the left side of the room, about midway through the room. In order to reach the treasure, the player must use (an upgraded) Kinesis pull. Therefore, even though it is possible to see the treasure early on in Chapter 1, it remains impossible to obtain it until Chapter 11.
It is possible to duplicate the treasure with the use of a glitch. If the player carries the treasure outside of the hangar bay (without adding it to the inventory) and causes a new area to load, then the treasure will respawn upon the hangar bay's reentry. This can be done infinitely, as long as the game is not saved during the process.
Possible Origins of Name
As stated at the beginning of the article, it is possible that 'Peng' is intended to be a sexual term of some sort. This is backed up by "Peng" being slang sexual term for an attractive woman in the United Kingdom. The treasure in the game represents a statue of a woman, which gives credence to this theory.
Another theory is that, in Norwegian, 'peng' is short for penger, which translates to 'money'. This could be considered another valid theory behind the etymology of the name "Peng", as the statue is the most valuable item in the game that Isaac can sell.