Not the way to start the week...Warning, snakes involved

[Acer]

I think it is a baby Black Rat Snake. If he's young, the head might not be a good indicator/might be out of proportion. And I don't it is really as triangular as it might look in the pic...the lighter color on the sides of the neck is blending into the background. They lose the bold markings as they age, turning mostly black (from a distance.)

Not poisonous, very beneficial, but they do have a penchant for the foundations of old houses, and go exploring from there.

[spoiler=Pic of a young black rat snake]

[/spoiler]