1)
What is the comparison to a snake?
1.
R. Yonah: While drinking the wine, he does not sense its damage. Rather, he goes in straightness. Afterwards, its strikes greatly.
2)
What is the meaning of "[uch'Tzif'oni] Yafrish"?
1.
Rashi #1: Is an expression of biting. The Targum of "b'Melamed ha'Bakar" (Shoftim 3:31) is bi'Frash Toraya. It says 'd'Nakat Parasha' (Bava Metzi'a 80a) - the pointy part of the plowshare that pricks the animal.
2.
Rashi #2: It separates him from life.
3.
Malbim: Tzafa is a kind of snake that also its Peresh (excrement) is poisonous and damages. Initially [wine] casts poison like a snake, and afterwards it makes its excrement like that of a Tzif'oni - burning venom.
