myself is a primitive that is useful when we want an agent to refer to itself while trying to address a different agent or agentset within an ask command or a reporter (e.g., of, with). For example, if we wanted to create a model within which turtles with the same color tried to find each other, we would write the following code:

ask turtles [
    face one-of turtles with [color = [color] of myself]
    forward 1
]

In the model example below, we have a model that is similar to the popular online game agar.io. We have many turtles that represent circles and they move around randomly. When two turtles touch each other, the larger turtle eats the small turtle. We use myself for two purposes: first to compare the two touching turtles within an ask statement in order to pick the larger one, and then to add the sizes of the two touching turtles.