Drake's dad is apparently dealing with a scary situation at home ... police say they responded to Dennis Graham's place after he got some odd and disturbing phone calls late at night.
Law enforcement sources tell TMZ ... someone called twice and texted Dennis over the course of 15 minutes Wednesday night, with the person on the other line allegedly rambling about Freemasonry and Dennis being Drake's dad, and that was enough to get cops involved.
Our sources say LAPD went to Dennis' estate after the alleged incident ... with cops taking an annoying phone calls report.
At this point, our sources say it's unclear who was contacting Dennis or what their motive was, but the case is under investigation.
There are a lot of fringe benefits that come with being Drake's pops -- like the Bentley his son once gave him on Father's Day -- but there are some headaches, too, for Dennis.