The action of forcing an object (usually a football) into the ground with tremendous force as a way of celebration or because you're f---ing hammered and felt like doing it anyway.
-- Definition of a "Gronk Spike," via Urban Dictionary
FOXBOROUGH, Mass. -- The Gronk Spike debuted on Sept. 26, 2010. After scoring his second NFL touchdown on a short pass from Tom Brady, Rob Gronkowski raised his left leg in Juan Marichal-like fashion, reached back with his meaty right arm, hopped three times on his right foot and fired the ball into the turf.