The Boiled Egg Vomiting Chain was a consecutive line of barfing in Niagara, triggered by Dwight after he was inconsiderate and peeled his pungent eggs at his desk when Pam and her queasy pre-birth stomach specifically requested him to not.
When Pam puked out her insides into the trash can, Andy also felt nauseous and tossed his cookies into the wastebasket under his desk.
Over at reception, Erin buckles and stumbles over towards the copier for a trash can.
Erin throws up for a second time, but doesn't make it and splatters her insides onto the carpet.
Angela doesn't even bother standing up and tries to cover her mouth with her palm; It doesn't work. Green goo flows out of the cracks between her fingers and splatters to the floor.
Only Creed isn't overcome with the urge, and calmly eats his ramen while looking surprised as he surveyes the office.
Pam gives Dwight a superior look and wipes off her mouth, leaving Dwight frozen with a half-eaten egg in his hand.
The vomit is fake, obviously, substituted with cream of potato soup.