Esus
Gallic (Continental Celtic) god, part of the trinity of "Taranus, Esus, and Teutates" according to Roman historian Lucan. According to Lucan, Esus' human victims were sacrificed by being tied to a tree and flailed.
Esus has been identified by some with Mercury, others with Apollo. However, a strict identification with a Graeco-Roman god is difficult, if not impossible. French folklorist Jean Markale identifies Esus instead with a type of god--the "horrible" sky god of magic, like Odin (whose victims were also tied to a tree and flailed), Math ap Mathonwy/Gwydion (lords of magic), and Uranus.
Esus has somtimes been written as Hesus, which has lead to some "scholars" to call him "Hu-Hesus" and identify him with Jesus and Hu Gadarn (a somewhat hypothetical Welsh god) together, a rather silly idea.