1:It is a violent take on the phrase, "Super happy fun time."
2:It is one of many groups who's regards towards death are that as of a fun past time or activity.
3:It is a military group based off of the ideals of the Russian covert ops group spetsnaz. Mostly dealing with technological warfare.
4:A party, guild, fleet, legion, and etc. As in a game where the prime objective is to accomplish the killing of one's foes.
"Hey I'm bored wan't to start a Super Happy Fun Time Death Squad."
"The SHFTDS was caught trying to rob a bank today, police are suspicious of the families as a role of instigation."
Tohishi Yamuri was the first to establish the official SHFTDS. It is now not recognized as being an existing part of the government.