You've met this dog before, you just didn't know it was called a dog. In Russian language the symbol @ is called собака (sobaka, a dog) or собачка (sobachka, a small dog). I don't know any other name for @ in Russian.
When you tell your email to someone, you say собака for @:
email@example.com — хххх собака ххх точка ком
(точка, tochka - a dot)
There are two theories about the origin of this word. One states that @ in certain Soviet computers had a shorter “tail” and looked more like a dog. Another version is that in some game called Adventure there was a dog following a player, and @ was its symbol.
Russian language can be cute as well! :)
Read also about what Russian email and soap have in common here.
Read a Wikipedia article about @ in Russian here.