Papa Wolf/Professional Wrestling

Uncle Elmer (Hillbilly Jim's uncle) was ordinarily an enormously fat, lazy, slow-witted buffoon. But threaten his nephew or one of his own two boys, and he might just sit on you until you beg for mercy.
Subverted with Dusty Rhodes, who tried to be this for his son Cody Rhodes in the summer of 2007 but was beaten senseless with a cowbell by Randy Orton for his trouble. After this, Hardcore Holly took over as Cody's father figure.
In Real Life, The Undertaker is this towards the younger superstars in the locker room (and that's everybody).
Kamala was enough of a threat already but some foolish individuals decided to try and attack his various managers anyway, making him even more dangerous.
In Real Life, Vince McMahon is an example of this. As Triple H said, "Hurt his wife or kids and he will use every resource he has to destroy." And don't even get me started if you try to touch his company.
At the 1000th episode of Raw, Paul Heyman thought it would be something to bring up children while arguing with Hunter, forgetting Hunter is this. When Heyman tries to explain himself, he had to handle the mother of his children... who is just as protective of them.