Showdown In Seatopia!
Written by
Bill Mantio (writer), Frank Robbins (pencils), Frank Springer (inks), Janice Cohen (colors), John Costanza (letters)
Released 1978
Solo graphic adventures printed in Man From Atlantis #3, April 1978 - 17 pages.
"Mark frees Elizabeth from Mr. Schubert's mind control, rescues the sailors and Dr. Simon from the sinking Seatopia, and takes the fight to Mr. Schubert."