Mmmmm ... Batman!

Big daddy Ben Affleck showed off his sexy torso and his bulging pecs when he wore a tight black t-shirt while running some errands in Santa Monica on Thursday.

The 42-year-old Batman vs. Superman actor looked particularity devastating in his black shirt, leather jacket, and a pair of slim-fitting jeans.

We kind of wish he had the bat symbol across that manly chest of his -- that's pretty much the only thing that could make us swoon more!