Utahraptor

Utahraptors are generally dangerous but are usally finished with single blows. However, they are hard to hit do to their ridiculous speed, making them, all in all, hard to kill. It is rare to find a utahraptor in the wild, though. And even so, they don't usally attack people unless they're in a bad mood, staight up starving, or(if they have that kind of personality)bored out of their minds. 

Utahraptors make great animal companions/familiars. They are strong, cunning, and competive. But utahraptors can serve villans, to. So you need to watch out for those guys. However, forming a bond with a utahraptor can take a long time(unless you're a druid).