The question isn't specific enough. Any dog can be vicious, it just depends on the environment they are raised in. If their owners are abusive then they might be more aggressive but every dog is kind until they're mistreated.
A large dog that has not been socialized with humans properly (or not at all) and/or has been treated inhumanely (by being teased, beaten, etc.) throughout its life. Strong breeds like pitbulls often get most of the blame for being the most dangerous and killer-type dogs in the world, when, in reality, it's the human behind that dog that is to blame.
All dogs are equipped with the tools necessary to kill a human. From the smallest toy breed to the largest. Some have even been bred for the art of killing. What makes it more likely that any dog will take a human life is as stated above, how the dog has been treated by humans.
the hippo
Of all the larger land animals of Africa, the hippo is the most dangerous and kills a number of humans each year.
no, its an anti-biotic that kills most bacteria.
That would be the pet Killer Bees.
most meat eaters and humans kill giraffes for meat and skin.
a dalmation
wolves don't have natural enemies but what kills the most of them is humans
There aren't good statistics on this - relatively few people in the United States are actually killed by a dog attack, and data from countries with more feral dogs (such as Mexico and China) is hard to come by. However, the "kind" of dog that kills tends to be an abused animal that has learned to fight for survival and doesn't trust humans. This animal may also be infected with rabies and in the final stages of dying from it.
Humans
Humans
chocolate kills dogs because most dogs are allergic to chocolate,which cant pass there throut without an allergic reaction
Probably a dog,or cat.