SB 10.15.23
so ’ti-viryo ’suro rama
he krsna khara-rupa-dhrk
atma-tulya-balair anyair
jnatibhir bahubhir vrtah
Translation:
O Rama, O Krsna! Dhenuka is a most powerful demon and has assumed the form of an ass. He is surrounded by many friends who have assumed a similar shape and who are just as powerful as he.