Since YJ Grayson's whole shtick is his laugh after he disappears, I would like to add on to it. What if he was the horror enthusiast of the team? Not just someone who likes horror media but whose whole personality revolves around it. Here are some headcanons:
001 .... When he's on missions, he would use the tension building cliches from slasher films like sound distractions or heavy breathing to terrify his opponents.
002 .... The team loathes when it's his turn for movie night because he will always choose a film that is either down right terrifying or a gorefest. He would lay on the floor kicking his legs unbothered by the disturbing visuals, reacting to each scene of characters being brutally murdered with a "that's got to hurt" or "yikes". There would also be some random trivia shared about the behind the scenes process of the film they were watching (not that everyone was paying much attention to when he rambled on).
003 .... He and wally will initiate competitions around Halloween to see who can scare the other the most. (usually involving no one else because of how intense the pranks are) One Halloween, Grayson was able to convince Wally that the entirety of Mount justice was haunted. The grand finale was him dawning a very elaborate costume soaked in fake blood to chase after Wally throughout the entire mountain.
004 .... His favourite movie is The Thing (1982)
005 .... Scarily good at the spider crawl need I say more?
