That is a fake account, there are over 70 accounts that are randomly down voting people. All of them are Rep 25 with no more steem than what was initially delegated. Here is a link semi explaining it and the actions that Steemit is taking. https://steemit.com/downvote/@quarantine/down-votes-accounts-use-for-harrassment

@quarantine account was only created a week ago, and seems it was created to try and deal with the barrage of downvote mania from ghost type accounts.

@patrice is the creator of @cheetah, and a witness, so it is unlikely they are behind it, but one never does knows. Best to not stress over it, even if all the accounts downvoted one account only it would have no effect.