The plural word phages refers to different types of phage, whereas in common usage the word phage can be both singular and plural, referring in the plural sense to particles of the same type of phage. Maloy et al: Microbial Genetics, 2nd ed., 1984, →ISBN, p. 81

Punching fast and furiously, I would beat the daylights out of them until they were bloody all over.

Baiting fish is not illegal in this state, but strongly frowned upon.

1908, Lucy Maud Montgomery, Anne of Green Gables