While fishing in a large river under overhanging trees along the bank, a fully grown water moccasin dropped out of a willow tree into the flat bottom boat. It was thrashing around, hissing, randomly striking and generally pissed off. I thought for sure that I was going to get bit. My dad scoped it up in a fish net and threw it out of the boat. I hate poisonous snakes and that was pretty scary, especially because it was so unexpected.