Based on this documentary, the sniffing of Whip-Its (container containing Nitrous Oxide) used to make whip-its cream can cause fatality among others. The users doing Whip-Its or "Noz" as it is sometimes called, as a harmless, laughter-inducing activity, can be deadly.
Not only that, the sniffing of the Nitrous Oxide from balloons as a laughter inducing sensation has similar effect. Such activity could cut off oxygen to some part of the brain which can caused convulsion and asphyxiation from nitrous oxide.
Whip-Its: Is Dangerous Teen Craze Making a Comeback? | Video - ABC News