Dr. Mario does an out-stretched arm spin and ends it with a stronger hit via an open-body bash. Dr. Mario is able to hover in the air when using this attack by repeatedly tapping the B Button. The move can gather vertical height once between landings if it is used and mashed while ascending (at the start of a double jump, for instance).
Dr. Tornado has the same effect as Mario Tornado, except that it is slightly stronger in terms of damage, has a lighter pull (and thus is able to rack up more hits if spaced properly), covers marginally less recovery distance, and the final attack sends opponents flying horizontally rather than vertically. Additionally, Dr. Mario doesn't yell "Yahoo!" or "Yee-haw!" when performing the attack, unlike Mario. In SSB4 and Ultimate, he will simply make a quiet grunt, identical to the one Mario uses for F.L.U.D.D. In Melee, the move has transcendent priority on all but the last hit.
In Smash 4, Dr. Tornado deals less damage but has more knockback on the last hit, capable of KOing more easily at high percents. It is also harder to break out of and has a much longer duration, while also having more range at startup. It has slightly more startup than before but is noticeably easier to mash, making it easier to use for recovery. It has more horizontal recovery distance but has significantly less vertical distance. It now also has transcendent priority on the last hit, but not on the looping hits.
In Ultimate, Dr. Tornado now hits seven times instead of five, and deals increased damage and knockback, making the move infamous for reliably KOing at significantly earlier percentages off-stage (the move is a kill confirm out of down throw akin to Luigi's variant). Additionally, Dr. Mario now gets percentage-based heavy armor during the move's startup, and the move is better for recovery as it gives him increased vertical distance and has decreased ending lag.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
Due to the changes Mario received in Brawl, and Dr. Mario retaining the same moveset from Melee, Dr. Tornado is the only special move of Dr. Mario's where he doesn't share the custom moves with Mario; he instead shares them with Luigi.
While Dr. Tornado does not have an origin in the Dr. Mario games, it is based off of Mario's Mario Tornado. The Mario Tornado is likely based on the Spin Jump move that originated in Super Mario World. The Spin Jump has lower vertical range than Mario's regular jump but deals more damage (or fully defeats enemies such as Koopa Troopas, who would otherwise be knocked out of their shells which could then be grabbed and thrown, or Galoombas, who would otherwise be knocked over and could be grabbed and thrown), offers protection from landing on many spiked normally-hazardous objects and enemies, and can break Rotating Blocks from above if Mario is not Small.
Since the move's appearances in Smash 64 and Melee, the spin jump has continued to appear in Super Mario games. While its higher damage and block-breaking power are now the job of the Ground Pound move instead, spin jumping tends to cause Mario to fall slower, briefly clear away fog, and bounce higher off enemies.
In Super Mario Galaxy and its sequel, Mario has access to a Luma-powered variant of the move, which acts as a one-hit attack, physical projectile reflector, and mid-air double jump/stalling technique.