In this paper we analyze the semantic and pragmatic properties of a colloquial interrogative construction attested in European Spanish, which we label invariable "qué" questions (IQQs). In doing so, we contribute to the better understanding of a relatively understudied phenomenon in Spanish, given that IQQs have been mainly approached from a purely syntactic standpoint. We claim that evidentiality and irony play a crucial role in the understanding of IQQs. Because of their special interpretative functions, as well as the fact that they do not appear to have a clear correlate in other languages, we believe IQQs pose a challenge to the second language student, which is why we further offer a step-by-step proposal to introduce IQQs in the Spanish as a second language class.