Though your post was not clear, I assume you are being sued by a former landlord for unpaid rent, fees, penalties or damages.
If so, and you fail to appear at court, the landlord will win a default judgment against you. It will include the original 'damages', plus attorney fees (if any), plus court costs, plus interest.
With the judgment, the landlord (now Judgment Creditor) can do the following:
1) Garnish your wages.
2) Seize your bank account.
3) Seize any exempt property or assets that you own.
4) Report your debt to the credit bureaus.
5) Generally hound you until either the judgment expires, or you do.