Lakitu originally appeared in Dr. Mario World. Now, however, Nintendo has confirmed that the character will be a proper doctor as well.
Dr. Goomba was also recently announced as a new character for Dr. Mario World. That one is an entirely new addition.
Dr. Lakitu and Dr. Goomba both go live in Dr. Mario World on April 26 at 11 PM PT / April 27 at 2 AM ET.