Phrase used in StarCraft 2 play, especially at the pro level, to describe adapting to a situation with a seemingly on the fly strategy that exploits a specific mistake made by an opponent that is unlikely to be repeated later in the game or in further games for that round if it were countered by using a conventional strategy. As an opponent would then be forced to react by changing their overall playstyle for the remaining games in the match, the targeted weakness will likely disappear. Thus a player would lose their metagame advantage of being able to predict where and when an opponent is open to attacks.
Comes from veteran Ukranian StarCraft progamer Aleksey "White-Ra" Krupnyk responding to a question regarding how he would handle an infamously tough match-up for him in an event, which due to his strong accent and odd use of English came out in a memorable fashion:
"Don't worry, I use Special Tactics this time, no problem."
White-Ra went onto win the match 3-0 and advance to the next round by playing standardized openings that moved into bizarre unit mixes and unorthodox usage of them that were unique to each game but in all cases exploited the same specific weakness in his opponent's strategy.
"Dave played a normal 3-gate robo opening, but then shifted into some bizarre 1 colossus and 4 zealots in 2 warp prisms to kill his opponent's workers and kite his marines away from the base at the same time."
"Well he must have used Special Tactics"
"He was pushing out of his main base with a ball of marines while expanding to his natural, so I used Special Tactics and dropped 4 blue-flame hellions to kill of his workers in the main, then picked them up and dropped them in front of his retreating marines while dropping 2 tanks behind his mineral line to pick-off workers as they're made and destroy his buildings."