"I see the big bulls."
Translation:Rōvī vandissa urnen.
"Vandyssy" is never the correct plural, though, unless I am very mistaken. That's only the plural for solar nouns in the second declension (which end in -ys). Vandis is a solar noun in the fifth declension (which end in -is).
"Rovyz" would be correct if "vandis" were in the nominative plural, but it's in the accusative plural, since it's the object of the sentence, not the subject.