The "tentacle blade instance" founded and made
popular by Southpaw refers to any instance in which a character has the will, means, and resources to
kill another character, and when given the opportunity, chooses not to with no further explanation. Most excuses given are the character forgetting to use their resources or calling them
arrogant.
Person 1: "Hey, why doesn't Doc Ock ever
kill Spider-man with the blades in his tentacles? He wants to
kill him and has so many chances."
Person 2: "That's a tentacle blade moment and bad writing."