Description:
Pound Cake might have messed up the mixture.
He is saying “UF.“
Credit goes to Shera5
http://vignette1.wikia.nocookie.net/mlp/images/f/fc/Scootaloo\_blows\_test\_tube\_out\_of\_her\_mouth\_S6E4.png/revision/latest?cb=20160410165837 <- Here is the original.