As you get closer to the swarm, the full magnitude of this event starts to dawn on you. You hear about a dozen people attempting to coordinate with each other. More than that, though, a persistent buzzing grows louder the closer you get.
When you break the tree line into the clearing where everything is taking place, it becomes clear that this Trapinch swarm isn't just Trapinches. Some larger yellowish pokemon are roaming around and a handful of large green ones are flying through the air, serving as some combination of generals and protectors.
Most of the other trainers there don't notice your arrival, but a nearby girl does wave you over.
"Hey, come join the fun!" Then she turns back to the battle and shouts, "Another fireball, Voren!"
SpoilerIt's a MAP! (This is about a quarter of the actual battlefield, just for scope's sake.) Normal battle rules apply with you just having 1 command/attack and whatnot per turn.