The Legend of Zelda: Majora’s Mask might be the strangest of all the Zelda titles, but it turns out that making it was so stressful, it gave several of its creators nightmares.

This new episode of the YouTube series “Did You Know Gaming” delves into the secret history of Majora’s Mask, a Zelda game that broke from the usual mold. The game tells a Groundhog Day-like story about playing the same three days over and over, trying to prevent the moon crashing into Earth.

The video is full of interesting tidbits, like the fact that Nintendo only gave the Majora’s Mask team a year’s development time—hence the nightmares and potential psychological scarring. All that stress also helped produce one of the best Zelda games out there.