Very, very simple. One user shows a picture of a pokemon. The user below must say that is a '____' Pokemon. (for example, a happy pokemon). However! The first user to say that must use a word beginning with A, the next B, and so on. Once a user has done Z, the next user starts from A again. So, for example:
User 1 Shows Picture of Pokemon
User 2- .... is an Abnormal Pokemon
Shows Picture of different pokemon
User 3- .... is a Beastly Pokemon
And so on. let's start:

User 1 Shows Picture of Pokemon
User 2- .... is an Abnormal Pokemon
Shows Picture of different pokemon
User 3- .... is a Beastly Pokemon
And so on. let's start:
