Many-banded krait
Also known as the Taiwanese krait or the Chinese krait, this snake is a highly venomous species found in much of central and southern China and Southeast Asia. If bitten and untreated, the mortality rate varies among different studies, anywhere between 25 to 35% to 70–100%. Not that comforting, we know.
Black-banded sea krait
The black-banded sea krait can mainly be found in most of the warm waters of the western Pacific Ocean. Their venom is actually ten times stronger than that of a cobra, making them extremely dangerous (!). Fortunately, this snake does not bite humans unless it feels threatened. Go figure.