A random term often used in many games such as the Warcraft III game, DotA (Defense of the Ancients).
It is usually used after getting killed and/or can be used as an accusation that someone is hacking, cheating, exploiting or playing unfairly in the game. (e.g. maphacking)
Tatsumaki has activated anti-hack. Their may be some brief lag for a period of time and any players who are hacking will be removed form the game.
The term "omgwthigo" is an acronym that stands for "Oh my gosh what the heck is going on?!" normally used when the person either truly is clueless on what is happening (usually wherever the other person is communicationg from) or as an expression while in a confusing online conversation, mostly with more than two people involved.
The longer version is more explicit, and self explanatory on what it is
"omfgwtfhifgo"
User 1 says: There is no way that this is happening
User 2 says: I know srsly this is mssd up
Used 3 says: Unbelievable
User 1 says: Yeah
User 4 says: omgwthigo