Wani (鰐?) was a dragon or sea monster in Japanese mythology. Since it is written using the kanji (from Chinese e 鰐 or "crocodile; alligator") wani is translated as "crocodile", or sometimes "shark" (from wanizame 鰐鮫 "shark").
Wani first occurs in two ancient Japanese "mytho-histories", the ca. 680 CE Kojiki and ca. 720 CE Nihongi. They write wani with the Man'yōgana phonetic transcription 和邇 and the kanji 鰐.
The Kojiki uses wani 和邇 several times as a proper name (e.g., the Confucianist scholar Wani, Chamberlain 1919:2,313) and as a sea-monster in two contexts. First, in the "White Hare of Inaba" fable, the gods try and fail to help a shiro 白 (lit. "white") "naked; hairless" hare that they found crying on a beach.
But the Deity Great-Name-Possessor, who came last of all, saw the hare, and said: "Why liest thou weeping?" The hare replied, saying: "I was in the Island of Oki, and wished to cross over to this land, but had no means of crossing over. For this reason I deceived the crocodiles of the sea, saying: 'Let you and me compete, and compute the numbers of our [respective] tribes. So do you go and fetch every member of your tribe, and make them all lie in a row across from this island to Cape Keta. Then I will tread on them, and count them as I run across. Hereby shall we know whether it or my tribe is the larger.' Upon my speaking thus, they were deceived and lay down in a row, and I trod on them and counted them as I came across, and was just about to get on land, when I said: 'You have been deceived by me.' As soon as I had finished speaking, the crocodile who lay the last of all seized me and stripped off all my clothing. As I was weeping and lamenting for this reason, the eighty Deities who went by before [thee] commanded and exhorted me, saying: 'Bathe in the salt water, and lie down exposed to the wind.' So, on my doing as they had instructed me, my whole body was hurt." Thereupon the Deity Great-Name-Possessor instructed the hare, saying: "Go quickly now to the river-mouth, wash thy body with the fresh water, then take the pollen of the sedges [growing] at the river-mouth, spread it about, and roll about upon it, whereupon thy body will certainly be restored to its original state." So [the hare] did as it was instructed, and its body became as it had been originally. This was the White Hare of Inaba. It is now called the Hare Deity. (tr. Chamberlain 1919:1,81-2)