Tetrahorse04V1

Tetrahorse04V1 was a trojan horse that impacted the online game based on the Calligraphy Deer series, Deer Tracks (racing game), launched in 2004 by Calligraphy Studios, founded in 2001. It was created by an employee who once worked at Calligraphy Studios around that time, and was launched into the server computers to mislead players to getting free deerlons by stealing their accounts and destroying games. Though ending in May of 2009, it wasn't until several months later that he was found as the one responsible, with him being fired permanently in March 2010, almost a year after the trojan was destroyed.

It was one of the most devastating viruses on ATBW Blog in 2008, phishing and hacking into player's accounts and to steal deerlons from them (all returned back to their accounts after being dismantled). It also dumped unnecessary programs on the game server, as well as inserting a malicious script that resets the chat 0.1 seconds after saying something in it. It did not harm any of the players' computers at all and it was easily avoidable by closing the game.

Unlike Merilhorse96V1 in 1996, Tetrahorse04V1 did not affect any of the company's computers or gain access into them, and did not steal any films or tv shows from those computers. It did however still cause damage to the company by damaging Deer Tracks online servers by $50,000 dollars to the server computers.