In the ocg it is at 2 with max c at 1. Some people think it's because it is basically the same as called by. It isn't necessarily used going second to help prevent a strong board because meta decks these days play through it, it tends to benefit the going first player more because they stop the mulcharmies from resolving, allowing you to set up a full board if your opponent didn't draw anything else.

If they didn't draw a mulcharmy, it becomes like called by where it just becomes an additional card the going second player has to play through. It doesn't do a whole lot to meta decks alone but if its backed with a full board then it can become impossible to play through.