The height of unnecessary ridiculous; the proverbial cherry on top of the Unnecessary Cake.

This comes from William Shatner's famous Spoken Word version of Elton John's "Rocket Man", where he performs the song as three different Shatner personalities, the last of which is the "Party Shatner".
Did you see that episode of "To Catch a Predator" where they had a cop in full-body tree camoflage jump out of the bushes and tackle one of the pedophiles as he walked away? That cop was the Party Shatner.
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