A synonym of "tremendous" (great, spectacular, outstanding, etc.), used in particular by fans of charismatic 1980s-era professional wrestlers such as Hulk Hogan, "Macho Man" Randy Savage, and the Ultimate Warrior. It is often used in a comically hyperbolic manner, reflecting the larger-than-life personas and exploits of samesaid wrestlers.
"When the Hulkster lifted that stinky, wart-infested 8'5", 1400 lb. Andre the Giant over his head and slammed him through the floor of the Silverdome in front of 340,000,000 screaming Hulkamaniacs...well, brother, it was tremend."