Star Trek: 10 Things You Didn't Know About The Cardassians
7. Does This Neck Tie Come With A Trick?
A running joke of Deep Space Nine was Odo's aptitude for the 'Cardassian Neck Trick.' What this is, exactly, remains unknown. However, there were clues throughout as to what it actually looked like.
Dr Mora Pol reminded Odo that when the latter was still in the former's lab, Cardassians would travel for miles to see the shapeshifter perform this gag. Dukat claimed that it 'brought the house down', while Odo's informant in Improbable Cause asked if he still performed it.
Odo's reputation preceded him, so much so that Quark - at that time still operating his bar under Cardassian rule - wanted Odo to demonstrate the trick in his establishment. This, as with everything Quark did, was to make a profit. Odo flatly refused.
Quark's demonstration - placing his hands on either side of his neck and puffing them out - suggests that the neck trick is an imitation of standard Cardassian ridges. This may seem a little anti-climactic though, when once has seen what a Changeling can really do.