look up any word, like guncle:
 
1.
A misguided statement for 'lets be serious', usually said for laughs.
Lettuce be cereal, I know you be 'mirin my aesthetics.
by DaUsualCrew December 28, 2011
 
2.
A fun way to say : Let us be serious
Person 1: Duur huur
Person 2: Lettuce be cereal

Person 1: Alright, whats up?
by Akiray December 28, 2011