Mick, aka the Smilodon Dopant, is the household pet of the Sonozaki Family and a supporting antagonist in Kamen Rider W.
Mick originally belonged to Raito, the youngest child of the Sonozaki Family. Despite being a house cat, Mick was intelligent enough to know how to use a Gaia Driver and Gaia Memory to become the Smilodon Dopant. As such, Mick was often used as an assassin by Ryubee Sonozaki.
Mick was sent after Kyoko Todoroki, fighting and defeating Kamen Rider Accel Trial in the process. However, Kamen Rider Double CycloneMetal manages to get Mick to stay still by exploiting a trick Ryubee taught him where he would expect food if a metal object was waved at him. Double then used his Maximum Drive to defeat the Smilodon Dopant, destroying his Gaia Driver and Gaia Memory. Following his defeat, Mick came over to Shotaro and allowed Akiko to pick him up and pet. He was adopted by Akiko soon after, and was happy to change owners as long as he was fed and petted.