Hitching a ride.

They're known to raid nests but I'm not sure about taking on larger animals than themselves...other than chickens, maybe. Most predators don't like to tussle with their food. I'm thinking the youngster made a naive mistake. Some woodpeckers can be the size of crows and crows are excellent aerialists. Had this been a crow, the weasel could have found itself taken to altitude and subjected to loops and rollovers of enough G force to shake it loose. What we see here is one reason that very few wild animals make it to reproductive age. You don't take on a larger critter with killer teeth, talons or beak that can bore holes in wood.

I hadn't seen that.

I've not heard of a woodpecker foraging on the ground. But that explains how the weasel was able to jump him.

I agree with Steven and guess the weasel was a youngster.

Woodpeckers are clinging birds but will eat ants if they're climbing a tree. They're very high strung, constantly alert and can be noisy. We have some in our back yard and I've never seen them on the ground. It is known, however, that some birds will sacrifice safety for food if really starving. You can get a few to come to your hand if they're desperate but I don't think I'd want a Pileated woodpecker eating grubs from my palm.

It's the silly laugh that gets to me.

sounds just like Mel Blanc.

the cartoonist's wife. About the only one he didn't do, outside of Disney.
Just a thrown-in comment. The Warner Bros. store found in many malls has cartoon reprints for sale, of course. One of the best memorializes Blanc. Shows all the characters he did standing near (not at) a microphone, with bowed heads.