You all are setting out extreme examples to make a point, but they aren't actually all that relevant to the mass/velocity discussion in terms of ballistics. If this keeps up, I think we're about five posts away from the "knocked a deer off his feet" post...
I'm just going to wait until Nosler comes out with a bonded bowling ball. There will be no guessing, then.
I ONCE KNOCKED A MONSTER MULIE DOE RIGHT OFF IT'S FEET! With a 3/4 GMC four wheel drive, right around 43 MPH. I would convert that to FPS and take a shot a ENERGY figured but I don't feel those numbers would make her anymore dead than she already was. She had to be all of 23 5/8" from ear tip to ear tip.

43 MPH = 63 FPS. Depending on the year of your truck and the load (how much weight was in the bed? Full tank of gas?) you can nail down your grains pretty tight (7000 grains to a pound).
Let's just assume your truck, all-in, was 5000 pounds. That's a 35 million grain projectile, right there. At 63 FPS, you're looking at 308,391 foot-lbs of energy. I assume you didn't get a complete pass-through, so we can believe that she absorbed all of the energy. But I also assume your truck didn't come to an instant stop the second you hit her, either - so a lot of that energy was left in your truck's forward motion. Hmmm... I think we're circling the answer to the question of just exactly how much energy it takes to knock a deer off of her feet!
Thread hijack complete... back to the matter at hand

I have some 110 gr .257 Accubonds I hope to have a chance to try on a thick deer this fall as long as they shoot well out of my new-to-me 25-06. I'll definitely report the findings...