Leonard flexed after throwing down a ferocious dunk. Kleber landed on his backside. Leonard and teammates Paul George and Marcus Morris Sr. punctuated the play by glaring and shouting in Kleber’s direction, an image immortalized on social media. (It even showed up months later in the groundbreaking of the new Clippers arena site — on the back of the hoodie Leonard wore to the event.) By the way, the Mavericks won that game, too.