The shake is based on the McDonald's mascot of the same name who was introduced in 1971, known then as Evil Grimace ... the Grimace's 52nd birthday with many taking to the 'Scary Grimace' trend ...

The shake is based on the McDonald's mascot of the same name who was introduced in 1971, known then as Evil Grimace, who would steal milkshakes from customers before the character's friendlier rebrand ...