Idioms have been traditionally described as fixed expressions, highly restricted in their realization. Corpus and experimental studies, however, have shown that they are more variable than previously thought. The issue of idiom syntax has received a renewed interest, since it also addresses the problem of how idioms are mentally stored. Another relevant topic is the role played by literal plausibility of idioms, which refers to the likelihood of an idiomatic expression for a plausible literal interpretation. In this research, we addressed both topics, by means of three cross-modal priming experiments, where canonical idioms and variants (i.e., passive form and left dislocation) were followed by words related to the idiomatic meaning of sentences ("break the ice-embarrassment") or literal meaning of single words ("break the ice-cold"). The results seem to indicate that idioms do not have a special status in terms of syntactic variability: they behave like literal sentences and do not lose their idiomatic interpretation if manipulated. Moreover, data reveal processing differences between literally plausible and implausible idioms. The results are discussed within current theories about idiom representation.