Spitting on a pigeon is much more difficult than the average person would guess. First off, a pigeon doesn’t like to be spit on (I doubt anything besides a seal enjoys such behavior). Secondly, it can be quite painful for a pigeon to be spit on.
Things that can happen when a pigeon is spit on:

1. They vomit popcorn even if they haven’t eaten popcorn.
2. They forget how to fly.
3. They become invisible and everything around them appears invisible to them. Basically, they end up in a world of nothing where they don’t even exist because they are invisible.
4. A hawk eats them.

A player gets one point for spitting on a pigeon and one point for each separate reaction by the pigeon. For example if you spit on a pigeon and it vomits popcorn and then gets eaten by a hawk then the player is rewarded three points.
A man in the Netherlands is said to have the only known spit in the world which results in a five point player. Though some question how he really knows whether the pigeon turns invisible after its eaten by the pigeon.