Light has properties of waves and particles and doesn't necessarily travel in "straight lines".
There is an interesting experiment (I will look up the original scientists who did it and post that info here) where they set up basically a cardboard circle in front of a wall and then shine a flashlight at it.
Interestingly enough, there is a shadow in the shape of a circle on the wall behind the cutout, but there is a bright spot in the middle of the shadow. How did the light get there? Well, the answer is, it doesn't move in a straight line.
I think your laser is doing the same thing, but the effect is probably exacerbated by the reflective properties of the metal wire that you are shining the laser at.
Please see the very informative comments below for more information about the experiment. It is referred to as the Arago/Fresnel/Poisson spot.