Like a figment, a pattern spell creates an image that others can see, but a pattern also affects the minds of those who see it or are caught in it. All patterns are mind-affecting spells. This impression is totally in the minds of the subjects. It is a personalized mental impression. Third parties viewing or studying the scene don't notice the phantasm at all.
All phantasms are mind-affecting spells.
The caster weaves it from extradimensional energies. Such illusions can have real effects. If a creature takes damage from a shadow illusion, that damage is real. Creatures encountering an illusion effect usually do not receive saving throws to recognize it as illusory until they study it carefully or interact with it in some fashion. A successful saving throw against an illusion reveals it to be false, but a figment or phantasm remains as a translucent outline.