Consider the following diagram of algebraic varieties:
$$mathbb{A}^0 to mathbb{A}^1 rightrightarrows mathbb{A}^2$$
Here the first arrow is the inclusion of the origin into the line, and the next two are the inclusion of the line into the plane as the X and the Y axes.
Does this diagram have a colimit in the category of schemes?
(The first arrowing giving inclusion of the point is not relevant; it just so happens that it was there when I met this question.)