You need: 3 friends, 4 computers and some time.
How: 2 friends get apexes, the other 2 get dino monsters.
Execution: The dinos will ram the apexes into the air and the apexes will send a 1v1 request in mid-air. The other apex will accept it, and they will be pulled into 1v1.
But theoretically they are still in mid-air, and in mid-air animals can't harm each other. So the 1v1 arena will crash like crazy.