The quantum surge was an energy wave, one of the results of the destruction of the Vok Planet Buster at the end of the first season of the Beast Wars cartoon.
Part shockwave and part energy/radiation wave- the radiation apparently modifying the affected Transformers to make them invisible to Vok defences-, the quantum surge was responsible for the creation of the first of the Transmetals, mutating Megatron, Cheetor, Rattrap and the temporarily mindless body of Tarantulas (his consciousness had been accidentally downloaded by Blackarachvia); Scorponok and Terrorsaur were apparently also affected, but fell into the lava pits near their base before the transformation could complete itself.
It was later revealed that various Transformers in stasis pods underwent a similar mutation, while residue of the wave remained around Earth to affect later arrivals to the planet. Another possible factor is that the surge may have resulted in creating the first known Fuzor variation.
The wave was unable to affect those who were in the CR chambers at the time- Rhinox and Dinobot had been incapacitated by cyber-venom during an earlier attack on the Axalon and Waspinator fell into a chamber during the initial tremors caused by the shockwave- or those activated on Earth, such as Tigatron, Blackarachnia, Airazor and Inferno, who were otherwise unprotected from the surge.