Valve might want to reconsider their planned 'anything goes' approach to content on Steam, after Abstractism - a game that had been apparently lurking around on the store since March 15th - had to be pulled from sale after a flurry of bad press. As reported by YouTuber SidAlpha in the video below, the game was being identified by many virus scanners as dangerous, and was devouring far more CPU & GPU power than intended, hinting at possible cryptocurrency mining. Beyond that, it was definitely generating sketchy Steam Marketplace items, some of which seem likely intended for use in scams.
Apparently developed by Okalo Union and published by dead.team (whose logo is a Guy Fawkes mask, of course) Abstractism claimed, on its surface, to be a minimalist platformer which rewarded very extended play with items. These could be sold on the Steam marketplace in exchange for Steam store credit, and some them were rather troubling. One in particular was designed to look exactly like a coveted and rare Team Fortress 2 rocket launcher if viewed through the Steam marketplace UI. The only real hint that it wasn't the gun you were looking for was the item's game of origin. A detail easily missed, as one person in the video below discovered when he found himself buying the fake instead of the real in-game weapon.
That particular incident set the ball rolling, and before long people were investigating Abstractism en-masse. It appears that Okalo Union began changing the art and description on that item to something more innocuous now that the story was gaining speed. Not long after, people started looking further into the game's possible state as a virus or hidden cryptocurrency miner. In the face of growing evidence, Okalo Union made the following and baffling statement via Steam:
"Bitcoin is outdated, we currently use Abstractism to mine only Monero coins.
Abstractism does not mine any of cryptocurrency. Probably, you are playing on high graphics settings."
As reported by PC Gamer, the Monero comment was later claimed to be a joke. Abstractism has now been pulled from sale. According to a Valve representative via PCGamesN, they have "removed Abstractism and banned its developer from Steam for shipping unauthorized code, trolling with content, and scamming customers with deceptive in-game items", which lends weight to the allegations. Right now it's not clear for how long the "unauthorized code" was in effect for, but even if it was only activated recently, then that raises some uncomfortable questions for Valve to answer.