okay so spock (the alien in blue) essentially goes into heat. like literal heat like an animal. Anyway, spock’s in bloodlust in this episode and must go back to vulcan to have sex with his finace (or someone. but its supposed to be his fiance) or he’ll literally die. this is called pon farr and some backstory spock is half human and thought he wouldnt go through pon farr so he abandoned his HOT fiance to fuck around in space except oops pon farr happens so. he and kirk (in yellow getting his tits cut open, he’s also spocks captain and best friend) and their other friend mccoy go to vulcan so he can have sex with his fiance or get married or whatever so he doesn’t die. but then spock’s fiance (t’pring) is like no i dont want to marry spock i want to have him fight someone to death (which she can do) and spock at this point is fully in the ‘blood lust’ and is basically not in his right mind and doesnt get what’s happening. and t’pring picks kirk to be her ‘champion’ in the fight (her logic is that if spock dies in the fight she doesnt have to marry him and if kirk dies, spock will be so upset with her he won’t marry her anymore anyway). anyway kirk doesnt know that its a fight to the death and so he’s like of course i’ll do this fight if it’ll help spock and then he gets told it’s a fight to the death and he goes WHAT and right afterwards spock slices his titties open like in the gif. also eventually spock and kirk roll around in the sand and kirk fakes his death and THIS somehow knocks spock out of his blood lust and he goes back to the ship super sad bc he’s killed his ‘best friend’ only to discover kirk’s alive and we see one of his biggest smiles of the series (a big deal bc spock is vulcan and they dont show emotion). anyway this aired as the season opener in 1967. know your history and all that happy pride
