Alas, this gorgeous beetle (Latin name Neoclytus mucronatus) does not have a common name. It’s a longhorn beetle, but that really doesn’t narrow it down past the family (Cerambycidae). A bunch of its cousins have common names like “ash borer”, but this doesn’t. What this beetle needs to be called is a wasp-mimic beetle, because, at a glance, it really does look like a wasp. Besides the bold red, yellow, and black coloration, the beetle waves its hind legs in such a way that the black sections really look like a wasp’s wings being held out behind it. (The beetle’s own, perfectly functional, wings are hidden under its elytra, like those of other beetles.)
Adults are about 8-23mm long (this one was about 15mm), and, like their cousins, eat dead and decaying tree matter. They live all over the eastern US, from Canada to Florida and west to Texas, and otherwise suffer from Wikipedia Stub Syndrome. I’m startled by this; this is such a strikingly beautiful beetle, why is no-one studying it?
This individual was identified by the kind people at iNaturalist and bugguide.