I had two big Styrofoam target blocks but I blew one up yesterday. I should have one left in the garage...have to check. You don't want to shoot the trees? (just kidding)
I can't use styrofoam as a target for this crossbow. It goes right through it! I just have a box stuffed with stacks of newspaper and cardboard. I have it packed pretty tight and it stops the arrows pretty well. Only thing is it makes the target kinda heavy.