@WoolleyDoog's mention of Terrell Suggs got me to thinking. Suggs was a monster. Ronnie Lott for USC when I was a kid. Gabriel "Senor Sack" Rivera of Texas Tech in 1982.
Chuck Cecil for Arizona. Cornelius Bennett of Alabama in '86. Teddy Bruski of Arizona in '93 or so.
In the past ten years I'm sure there's been a few great ones but I don't remember anyone who "scared" me