Oracle Database Discussions

hi bolow is the index creation scritpt i have created it in on of the table

CREATE UNIQUE INDEX TESTUK_05
ON TEST (COL1_NO,
             COL2_NO,
             COL3_DATE,
             COL4_NO DESC)
PCTFREE 002
INITRANS 5
STORAGE (
          INITIAL 200M
          PCTINCREASE 0
        )
TABLESPACE USERS;

but when i m quering table user_ind_columns it is showing me some different column name in place of last column which is "col4_no"

select TABLE_NAME,INDEX_NAME,COLUMN_NAME from user_ind_columns where table_name='TEST' order by INDEX_NAME;

TEST      TESTUK_05            COL3_DATE
TEST      TESTUK_05            COL2_NO
TEST      TESTUK_05            COL1_NO
TEST      TESTUK_05            SYS_NC00012$

PLEASE TEL ME WHY IT IS GIVING COLUMN NAME AS "SYS_NC00012$" INSTEAD OF COL4_NO