The first intertitle: "Once upon a time" (situational irony)
The first intertitle in Un Chien Andalou, "Once upon a time," is to some degree ironic, as it suggests the beginning of a fairy tale. But the film immediately disrupts these expectations by following that intertitle with a violent scene of Buñuel slicing a woman's eye with a razor.
The last intertitle: "In springtime" (situational irony)
The film's last intertitle, "In springtime," also disrupts the viewer's expectations in an ironic manner. Following the couple's encounter with the tattered box and white linens on the beach, this intertitle leads the viewer to expect a scene of rebirth and renewal (characteristic of "spring"). In fact what follows is a shot of the Woman and the First Man buried up to their torsos in sand, static and disheveled.
The cloud passing over the moon (situational irony)
In the film's first scene, just after Buñuel has sharpened the razor blade, he looks up from the balcony at the moon. The film cuts to a close-up of his opening the Woman's eye, and then to a shot of a thin cloud passing over the moon. This shot leads us to expect that we will be spared having to watch Buñuel's slicing the Woman's eye, as the thin cloud over the moon figures as substitute for the slicing motion. But the film ironically disrupts that expectation, as it immediately cuts to an extreme close-up of the eye being sliced.
The Woman's exiting the apartment onto the beach (situational irony)
At the end of the Woman's final confrontation with First Man in the apartment, she sticks her tongue out at him and charges out the room. We would, of course, expect her to enter another room, in the apartment, but in fact she walks onto a windy beach, where she greets her lover. The films edits this sequence so that the transition is entirely continuous, and even has the Woman's line of sight meeting that of her lover on the beach.
