From The Happening
[to concerned teachers
] Alright, there appears to be an event happening. Central Park was just hit by what seems to be a terrorist attack. They're not clear on the scale yet. It's some kind of airborne chemical toxin that's been released in and around the park. They said to watch for warning signs. The first stage is confused speech. The second stage is physical disorientation, loss of direction. The third stage... is fatal.