An anonymous Instagram user is taking on the art world. His targets? Artforum, Richard Prince, and the Frieze Art Fair, along with pretty much everyone and everything in between. The account’s handle is @icallb, denoting the user’s ongoing goal of “calling bullshit” on artists, dealers, institutions, and the occasional celebrity (Jessica Biel found herself a target after appearing on the red carpet at MoMA, while all James Franco had to do was continue to exist).

The user recently found himself in a tussle with controversial art dealer Stefan Simchowitz, in which Simchowitz attempted to call BS on the original BS caller. In a series of Instagram comments that were later uploaded as a post to the account, Simchowitz suggested: “why don’t you show us some things that you think are not bs. Show us some art that you like. Negatives need a positive or is this just your side show for 3 minutes of hater fame.”  While he may be right, Simchowitz seems to have misconstrued the account’s purpose—calling BS on people for their perceived poor taste and lapses in judgment, if we’re to glean anything from its name.

We’ve all heard the old adage, “if you don’t have anything nice to say, don’t say anything at all,” but unfortunately, nice things are rarely as funny (or as viral) as not nice things. Depending on who you ask, the anonymous Instagrammer is either launching uncalled-for attacks, or saying the things we all wish we could. But if some random person hiding behind an Instagram account doesn’t keep the art world in check, then who will?

Below are some of @icallb’s zingers. Now go set your Instagram accounts to private, because you never know who’s next.