The account is just downvoting with low power (less than 0.01). It is a way to observe who is misusing downvoting power. If someone is found misusing downvoting power, then a group of people MIGHT upvote those downvoted posts.
Unfortunately, to track downvotes, he have to follow same downvote trails he wants to track. You can visit downvoting history of this account to track and collect data too.
The damage is negligible compared to the data it collects.