fourth clue

Edit Answers
12345678910111213
Across
  1. 4. Pen for Sisyphus, Tantalus and Ixion
  2. 5. Field, or Ride, at their wittiest
  3. 7. Ascending and Descending artist
  4. 8. dad washer?
  5. 10. __ Cathy
  6. 12. 10^10^100
  7. 13. Badinage
Down
  1. 1. across+ down
  2. 2. Serpentine 69
  3. 3. Irish crack?
  4. 6. Unwilting pink flower
  5. 9. __ Don't talk back
  6. 11. What the Romans (and marines) said always