The Bad Weather Friend by Dean Koontz

Benny is so nice they feel compelled to destroy him, but he has a friend who should scare the hell out of them.

Benny Catspaw’s perpetually sunny disposition is tested when he loses his job, his reputation, his fiancée, and his favorite chair. He’s not paranoid. Someone is out to get him. He just doesn’t know who or why. Then Benny receives an inheritance from an uncle he’s never heard of: a giant crate and a video message. All will be well in time.

How strange—though it’s a blessing, his uncle promises. Stranger yet is what’s inside the crate. He’s a seven-foot-tall self-described “bad weather friend” named Spike whose mission is to help people who are just too good for this world. Spike will take care of it. He’ll find Benny’s enemies. He’ll deal with them. This might be satisfying if Spike wasn’t such a menacing presence with terrifying techniques of intimidation.

In the company of Spike and a fascinated young waitress-cum-PI-in-training named Harper, Benny plunges into a perilous high-speed adventure, the likes of which never would have crossed the mind of a decent guy like him.