Intimidation

It is absolutely amazing! Think about this in a pure black rat ninjitsu deck.. Holy crap!

intimidation with larceny and a few megrims

intimidation is one of the best card i ever used it helps out killing the other player because once you get it out u can attack even more freely with your creatures. I use it in my blk suiside deck. works very well too.

Intimidation is a mediocre card, firstly black happens to be the most popular color currently, so you are most likely to face a black deck where intimidation does you nothing. Secondly even if your creatures are unblockable against a non-black deck, if you attack with everything, the next turn it makes sense that you will then be hit with everythingm, making it a slugfest. Thirdly there are several cards, such as meekstone, ensnaring bridge, crawlspace, etc. that make it so attaking is either ill advised, or downright impossible.