The Attack of the Killer Forest was a major catastrophe and one of the most notorious controversies in the history of the Quidditch World Cup, as well as the worst exhibition of temper ever given by a player.
Niko Nenad, a Beater for the Romanian side, had enlisted local Dark Wizards to jinx the entire forest nearby to come to life, rip their roots out of the ground and trample the stadium. What had begun as a fun, innocent game of Quidditch had ended as a bloody, violent battle between trees and wizards. Nenad was not prosecuted as he had been killed early on by a particularly violent spruce.
- Pottermore (First mentioned)