  We present very early photometric and spectroscopic observations of the Type
Ia supernova (SN Ia) 2023bee, starting about 8 hr after the explosion, which
reveal a strong excess in the optical and nearest UV (U and UVW1) bands during
the first several days of explosion. This data set allows us to probe the
nature of the binary companion of the exploding white dwarf and the conditions
leading to its ignition. We find a good match to the Kasen model in which a
main-sequence companion star stings the ejecta with a shock as they buzz past.
Models of double detonations, shells of radioactive nickel near the surface,
interaction with circumstellar material, and pulsational delayed detonations do
not provide good matches to our light curves. We also observe signatures of
unburned material, in the form of carbon absorption, in our earliest spectra.
Our radio nondetections place a limit on the mass-loss rate from the putative
companion that rules out a red giant but allows a main-sequence star. We
discuss our results in the context of other similar SNe Ia in the literature.
