SAN FRANCISCO (CBS SF) — Pokémon Go mania is truly manic.

Two weeks after posting its highest one-day surge since 1983, Nintendo stocks plummeted 18 percent Monday.

The fall was blamed on investors realizing the electronics/software company doesn’t actually own the popular game that is sweeping the globe. In just one day, Nintendo lost $6.7 billion in market value.

After Pokemon Go’s release on July 5, Nintendo stock prices surged 24.5 percent, to $193 on July 11, adding $7.5 billion to the company’s market value. Apparently, many investors were seeing dollar signs because they thought the company actually created Pokémon.

Nintendo released a sobering statement Friday saying the company only owns 32 percent of The Pokémon Company. The Kyoto-based company’s “effective economic stake” in the app is only 13 percent according to Bloomberg.

In fact, Pokémon Go is a joint collaboration between The Pokemon Company and San Francisco-based software developer Niantic Labs.

The game sends users on a virtual Pokémon scavenger hunt. The game is so popular, police have issued warnings to entranced players. Some have been injured, walking into trees and parking meters, others have wandered onto private property, and still others have even been robbed of their cell phones.

The research firm Sensor Tower told Fortune that since its release, Pokémon Go has been downloaded more than 40 million times, “and has earned more than $45 million in net revenue worldwide.” How much of those earnings will trickle into Nintendo’s coffers remains to be seen.