The mules from Bryan Cranston's and Aaron Paul's Twitter are a reference to the Los Pollos Hermanos commercial in "Kafkaesque" (S03E08) : r/breakingbad
MAHONEY MULES & HORSES - Mahoney Mules & Horses
Um… March 3rd is National Moscow Mule Day! / #MoscowMuleDay | Foodimentary - National Food Holidays