Lovely pen doodle...it's all fluid and catlike. You've got tigers down very well! I can't believe you did this in 5 minutes. :)
Only critiques are that the colouring could be a bit more finished, and the toes on his left back foot seem to be shrinking a tad too much as you go down the foot...but since this was just a doodle, I'm being overly nitpicky. ;) Good work!
5 min? You're godly with that pen. The shading blends well with the picture making it come alive. You've even added the WHISKERS, which I can rarely make to create a realistic picture. I only ask that the white should be a bit more throughly shaded and a tad bit visible.