If one borrowed an ox on the assumption that it is innocent and it is found to have been warned for goring, then if it gored under the borrower's care, the owner pays half-damages and the borrowers pays half-damages.

But why? 

Borrower: “I borrowed an ox, not a lion!” 

Owner: “I told you that it was aggressive, so you had to guard it. And even it were innocent, you would pay half damages.”

Borrower: “For innocent, the payment comes from its body.”

Owner: “Even so, you would then repay me for the ox.”