Arnold Schwarzenegger ran errands in Brentwood on Wednesday, and we couldn't stop staring at his massive arm muscles. Sure, we know he used to be a bodybuilding champ, but seeing bulging biceps on a man old enough to be a grandfather is kinda gross!

In other news, Arnie is nearly done shooting Terminator: Genesis, in which he is reprising his role as a cyborg. So how are writers and producers handling the story 30 years later? Remember, the first Terminator flick came out in 1984, back when Arnold was kind of a babe -- and before we learned that he had cheated on his wife Maria Shriver with the family's housekeeper.

"The way that the character is written, it's a machine underneath," the 66-year-old actor said in a recent interview with MTV News. "It's this metal skeleton. But above that is human flesh. And the Terminator's flesh ages, just like any other human being's flesh. Maybe not as fast. But it definitely ages."

The fifth installment of the Terminator film franchise is scheduled to hit theaters in July 2015.