Oracle start up problem

[stecal]

SQL> startup mount
SQL> alter database datafile 
  2 'D:\ORACLE\ORADATA\DB00\INDX01.DBF' 
  3  offline drop;

Database altered.

SQL> alter database open;

Database altered.

SQL> drop tablespace indx including contents;

Tablespace dropped.

Wait!! Son-of-a-biscuit-eater! That was my index tablespace I just trashed.