Depends on the person, they're just different and varying personalities.
I wouldn't say they're not human, they obviously are human, but they just operate in a different way to what most people would call "normal". Whether they're a wolf depends entirely on how much harm they do to you.
On the lower end there are emotional vampires who will suck your time and energy and they generally like people pleasers and people who struggle to say no, they are needy and clingy and constantly victimising themselves.
Higher up i guess are people who will tell you everything you want to hear and will cheat/lie/deceive/be devious in order to get something they want off you. Con folk basically... and if you push back on it they will become extremely abusive.
Higher up still are malignant narcissists who are bullies, want attention, admiration, genuinely feel like they're better than other people and have no issues using people as stepping stones. All very nice at the start though, but the nasty side soon comes out. Everything is about them, they usually are in leadership positions because of bolshy self promotion and ruthlessness.
Above that are sociopaths who couldn't give a fuck about right or wrong, take advantage of others with absolutely no remorse, are extremely charming and witty (like malignant narcissists), think they're better than everyone else, and are often criminals.
Above that? Psychopaths... purely because they don't actually have any remorse because they don't really feel emotions the same way as other people if at all. They can quite easily drown a puppy and feel zero shits. A lot of pyschopaths actually aren't nasty people, they're just people with no emotions, but if they are nasty people and they are also pyschopaths then yeah... dangerous. But any of these folk are not good for you to be honest.