Answer: a thrombus
A thrombus may also form in your heart
The snakes have evolved resistance to the blowfish poison, tetrodotoxin (TTX), by preying on rough-skinned newts, which also secrete the toxin. Some newts are so poisonous that they harbor enough TTX to kill a roomful of adult humans. ... The answer lies in the evolutionary back-and-forth between newts and garter snakes
it is caused by relaxation of smooth muscle cells that are in the vessel walls which in the large arteries.