Doctor Who: 8 Stories That Would Have Made Wonderful Regeneration Stories

4. "The Celestial Toymaker"

When the decision to replace William Hartnell came, it brought a question as to how to actually replace him. Supposedly, the original plan was to write him out in "The Celestial Toymaker;" the six-part serial was written under the impression it would bid Hartnell a farewell, but instead of regeneration, the Doctor would transform by means of a prank. The Toymaker was going to change the Doctor's body and refuse to change him back, leaving him stuck looking like Patrick Troughton. With a few adjustments, the plan to have the Celestial Toymaker force the Doctor to change may have worked. The title villain presents a menacing threat to the Doctor, utilizing trickery to deceive and separate the Doctor and his companions. His antics leave the audience wondering how exactly the Doctor will surmount having been turned invisible and made mute. Maybe the Celestial Toymaker wouldn't have needed to change the Doctor's face - maybe the candy he eats at the end, which comes from the Toymaker's game and leaves him in pain, could have triggered the first ever regeneration. Fortunately, William Hartnell got to stay for a few more serials, taking his leave at the end of "The Tenth Planet," which introduced the cybermen. It's very likely the inclusion of the shocking, first regeneration helped establish the cybermen as formidable Who foes.