They signed an anaconda mortgage to cover their new business loan.
anaconda mortgage
idiomA loan arrangement in which all of the money borrowed from a lender, for whatever purpose, is secured by one's home, land, and other property.
Origin
disputed originAn allusion to being trapped in the crushing coils of a large constrictor snake, such as an anaconda, suggesting the crushing burden of such debt.
The bank required an anaconda mortgage, meaning the couple had to use their house as security for all their debts.
Before agreeing to the terms, the lawyer warned that an anaconda mortgage would place the family's entire property portfolio at risk if they defaulted on any single loan.