It was 2016. The Summer Olympic Games in Rio had started. The crowd's cheers enveloped the stadium. 35 competitors were visible from within, waving to the audience and grateful to compete for the fifth time. They were warned about the dangers of the zika virus and water pollution, but were told it was safe to compete. They didn't know how bad things were about to get...they didn't know that all of them would end up dying...
First up was a swimming event. Everyone swam like their life depended on it. However, Sonic's life vest was not on properly. It fell off, causing him to almost drown. Lifeguards successfully saved him from death. However, he was contaminated by the water, and got extremely sick. He could not be saved. Metal Sonic also stopped functioning entirely during the event because he's a robot and robots and water don't mix. Dr. Eggman attempted to fix him, but got electrocuted and died before he could.
Then came the Equestrian event. The horses were abused and grumpy. They kicked Luigi, Shadow, and Larry in the stomach. Only Shadow survived because he's that tough and edgy, but later died from getting the zika virus. Luigi lost his will to live and requested assisted suicide. Larry died after 10 minutes because he's weak enough to get killed by a pot-bellied plumber.
Vector later got into an argument with Wario over who was better at the javelin event. Vector lost his patience and brutally murdered Wario. Waluigi was especially hurt, because he was best friends with Wario. Mario felt Waluigi's pain and they comforted each other. They decided that life wasn't worth living anymore, and shot each other.
Seeing all the fatalities, Nabbit refused to participate in the 100m. He ran away, but got caught and forced to run. After still refusing to compete, they locked him in a prison cell and starved him to death.
Slowly but surely, all the competitors died, from illness to murder to suicide. All but one. Vector was the last one alive. He muscled his way through all the pain he went through. However, he became a psychopath in the process. The emotional and physical baggage he had to carry made him lose all emotion. He killed five people for sport and had to be humanely euthanized.