If you are given poison, you may choose to flip the bad gas token. If the token lands blank side up, there is no effect, and play proceeds as usual. If it lands bad gas side up, immediately move your belt down one notch. Additionally, neighboring players might be affected by your gas. The player to your left and the player to your right must check to see if they are affected! They each flip the bad gas token. If their flip lands gas side up, then they are forced to purge and immediately move their belt down one notch. If both your left and right neighbors purged, you are sickened by their acts and must move your belt up by the same number of spaces as the poison you originally received.