That's One Big Frog!

(2) Aaron held out his arm over the waters of Egypt, and the frogs came up and covered the land of Egypt.

(2) ותעל הצפרדע AND THE FROGS (lit. frog) CAME UP — Really there was only one frog, but when they struck at it, it was split into many swarms. This is a Midrashic explanation of the usage of the singular noun here (cf. Sanhedrin 67b; Exodus Rabbah 10:4). But as a literal explanation one must say that the swarm of the frogs is denoted by the singular form. Similar is, (v. 14) “and there was the כנם” — the swarm of insects, in old French pedulier; i. e. a swarm of lice. So, too, here, ותעל הצפרדע means: and there came up a grenouillière (old French) i. e. a swarm of frogs.

"And the frog came up, and covered the land of Egypt." (Exodus 8:2) Rabbi Eleazar said: It was one frog, which bred prolifically and filled the land. This is a matter disputed by Tannaim. Rabbi Akiba said: There was one frog which filled the whole of Egypt [by breeding]. But Rabbi Eleazar ben Azariah said to him, ‘Akiba, What hast thou to do with Haggadah? Cease thy words and devote thyself to ‘Leprosies’ and ‘Tents.’ One frog croaked for the others, and they came’.