1. The snake that convinced Chavah to eat from the Tree of Life caused the souls of her descendants to be Tamei.
2. The Mishnah states that on Shabbos one is allowed to break a barrel of figs in order to eat the figs.
3. There is a dispute about whether one may make a small hole in the cover of the barrel (see above, #2).
4. One is permitted to put a vessel into a pit in order to keep it cool.
5. A person is forbidden to act in a manner that gives the appearance of transgressing Halachah (Mar'is ha'Ayin).
A BIT MORE
1. The Gemara states that the snake had relations with Chavah, an act which somehow affected her children. This Tum'ah was removed from Bnei Yisrael (and all future converts, as their Mazal was present) when they received the Torah, but remained in the Nochrim.
2. Since the barrel becomes ruined, there is no prohibition against constructing a vessel. However, one must not intend to make the barrel into a vessel, because such intention will render his action a transgression of the Melachah of constructing a vessel.
3. Rebbi Yehudah: It is forbidden. Chachamim: It is permitted.
4. We are not concerned that one will smooth out the floor of the pit before he puts down the vessel.
5. Rav says that one is not allowed to do so even in private.