What does Boxing Day have to do with boxing?
Old English snægl, from Proto-Germanic *snagila (cf. Old Saxon snegil, Old Norse snigill, Danish snegl, Swedish snigel, Middle High German snegel, dialectal German Schnegel, Old High German snecko, German Schnecke "snail"), from *snog-, variant of PIE root *sneg- "to crawl, creep; creeping thing" (see snake (n.)). The word essentially is a diminutive form of Old English snaca "snake," which literally means "creeping thing." Also formerly used of slugs. Symbolic of slowness since at least c.1000; snail's pace is attested from c.1400.
(1.) Heb. homit, among the unclean creeping things (Lev. 11:30). This was probably the sand-lizard, of which there are many species in the wilderness of Judea and the Sinai peninsula. (2.) Heb. shablul (Ps. 58:8), the snail or slug proper. Tristram explains the allusions of this passage by a reference to the heat and drought by which the moisture of the snail is evaporated. "We find," he says, "in all parts of the Holy Land myriads of snail-shells in fissures still adhering by the calcareous exudation round their orifice to the surface of the rock, but the animal of which is utterly shrivelled and wasted, 'melted away.'"