Don Quixote; it may refer to the moment when don Quixote informs Micomicona (as he imagines; the priest in fact) that he has already killed the giant Pandafilando (a wineskine; in the background, observed by an sceptic figure; the innkeeper?).
Also in the illustration sancho, sticking out his head from behind the wall.
Don Quixote's figure, oniric, without face and skeletal, is absolutely remarkable and highly suggestive; also the female figure, resolved with a red cloak.
Many of the elements of the illustration are characteristic of Dalí (the ants on the wall, the phallic red figure, the desert landscape...).