I'm fairly certain I have the answer for this:
Mighty Mudkip received 6 down votes on 1 answer which would normally take his starting 20 points total to -40, but since you don't lose any points when an answer is converted into a comment he remained on 20 points.
When an answer is converted into a comment the up votes/down votes you receive remain on your profile but do not add on/subtract from your points total. See question here.
It seems he then received one up vote on another answer which brought his total points total up to 30 points.