ei ei mun!
Catchphrase of Umamusume's Matikanetannhauser. Usually said with both fists clenched like the ganbaru pose but with arms spread further apart.
This phrase is memetic enough to overflow to the real-life Matikanetannhauser, with tweets of images of said horse being flooded with "Ei, ei, mun!" comments. Even NHK's official Twitter account has taken part in this.