Is it?

Origins
This is a direct excerpt from the dialogue of the Halo 2 video game by Bungie. At one point in the story, the playable character Arbiter is told that the topic of which he speaks is heresy. His succinct (and infinitely quotable) response is, "Is it?"

By no means an indelible law, the phrase (or an alternate) is generally expected to appear amidst any dialogue at least once. Little notice is taken when it does not, however.

In HMP vernacular, the phrase is malleable to such a degree that it now includes any pronoun paired with a suitably conjugated linking verb.
 * 1) Examples of such interpretations include "Did he," "Will they," "Are you," and so forth.
 * 2) On occasion, HMP members have been known (both intentionally and by accident) to pair a pronoun with an inaccurately conjugated verb, which often results in additional hilarity.