The New York Giants run a lot of man coverage concepts under aggressive play-caller Don ‘Wink’ Martindale, so the green-dog blitzing concept isn’t insignificant, nor is it a strange cousin of Clifford.
A green-dog blitz is a defensive action where a defender rushes the quarterback after his man coverage assignment stays in to pass block. This is typically executed by a linebacker, but not always. The offense’s protection struggles to adapt to the late rusher, and an indecisive quarterback could find himself on his back if he can’t find a target or extemporize.
When the offense uses a six-man protection package against a defense, who is typically in man-coverage, and the running-back stays in to pass-block, the defender assigned to the running back comes as an additional member of the defense’s pressure package.