Yuudachi (; Literally meaning "Evening Thunder Shower in the Summer") is a missing-nin from Amegakure. He and his partner Ryuusui are looking for a drink when Jiraiya lures and captures them in his toad. When the Ame-nin refused to tell Jiraiya any information on Pain, the Sannin uses a feather to tickle-torture Yuudachi into giving him the info. When this failed, Jiraiya transformed Yudachi into a frog, which cowarded Ryusui into divulging info about Pain.
(Source: Narutopedia)