Not just grass-like, this is another kind of grass. One that may have to be showing flower or seed plumes to be positively identified.

so, i've found one of those grow in the backyard and after couple of weeks it has grown to 7 inches. i don't see any seeds. here is the photo. could this be crab grass???

ok, so here are few more photos of a fully grown plant (so it seems) that i found on the other side of my perimeter wall. looks like the same plant. what is this thing?

Those last pics look rather like Bermuda grass or bentgrass. Doesn't seem to be the same as the first pic -- are you sure that last clump is only one plant?

that last clump is not just one plant. there is one i found in my lawn (i think) and some other weird ones. here is the photo of what seems like fully grown one.