Either spiking people's drinks or sieg heiling, but probably both

Also clearly the bouncer did get assaulted right before the epic jump attack.

The classic good 'ol boy tactic, you see it as early as high school bullying. They know that they're well-liked and will weaponize it. They're at least intelligent enough to know when to use their social capital to their advantage. The gist goes that when the victim begins to fight back, the aggressor exaggerates their hurt to get whatever authority members that are in on the schtik with them to punish the victim.