No idea what it's scientific name is but I call it foxtail grass. Mine is an annual weed I try to remove before the seed head starts shattering.

It is dangerous for pets as the barbs on each seed go one way and the seed can work its way beneath the skin and even go traveling through the body.. Many other grass seeds are dangerous for the same reason.

One of the wild barleys, maybe hordeum murinum "mouse barley".