Psedonym for Commander Riker from Star Trek the Next Generation. The name originated from the observation that if Riker has a beard in any given episode, that episode will be a good one (and, consequently, a beard-less Riker indicates a sub-par episode). Over time, "Beard" came to replace Riker's name, in that he can be referred to simply as "Beard" (or, the less cool-sounding, "The Beard")
Nobody messes with Beard, not even Picard.
Beard singlehandedly saved the Enterprise.
Wow, Beard went crazy in this episode!