The Doctor has gone through many regenerations, and each new avatar of the Time Lord/ Timeless Child has had their distinct personality, traits, catchphrases, and the various ways they would handle a bad situation. However, one amazing quality remains through each regeneration on Doctor Who: the badass behavior. This connects the different versions of the character together in moments of sudden bravado and valor which make audiences love them even more.
Sudden displays of musical ability, face-offs against a universe full of bad guys, and refusing to give in to bullying is an everyday affair for The Doctor, but some moments truly stand out as the most badass in Doctor Who.
Never Trap The Doctor
The wise yet witty Eleventh Doctor found himself surrounded by one of the most intimidating foes of Doctor Who in "Time Of The Angels". What began as an episode with a single Weeping Angel ended with River, Amy, Eleven, and the others trapped by hundreds of them.
In this moment, the Doctor is further taunted by the Angels who use the voice of a long-dead Bob, making him extremely angry. The biggest mistake that the Angels could have made while setting a trap is putting him in it, and then further prodding him made him think faster and smarter which the villains failed to take into account. The Doctor could be deadly, but even deadlier when put in a spot.
The Doctor And His Guitar
"The Magician's Apprentice" may or may not be considered one of the best two-part stories on Doctor Who, but audiences got to see the most rockstar versi0n of the Doctor when Clara finally found him — atop a war tank, playing an electric guitar with shades on. The scene was a delightful juxtaposition of modern and medieval with a badass Doctor at the helm.
One of the reasons why the Twelfth Doctor got some resistance at first was because he was the oldest Doctor to be introduced after the youngest one, but Twelve was not any old boring man. He had the chutzpah of a younger man and his style surpassed most other Doctors, which was visible at this moment.
Saying No
There were several clues through the first season that pointed to Rose being the Bad Wolf. When the episode arrived, it was obvious that both the Ninth Doctor and his companion would have some renegade moments.
When the ultimate Big Bads, the Daleks, appeared on "Bad Wolf" and captured Rose, they expect the Doctor to bow down to their demands. In one of the greatest moments of Doctor Who, he said a simple no. The Doctor sent out a strong message, that he doesn't deal with terrorists, and stands by his morals in a difficult situation. This, ultimately, shows a side to him that fans hadn't seen before.
The Pandorica Speech
"The Pandorica Opens" saw one of the most epic speeches by the Eleventh Doctor in trying to protect the Pandorica, not knowing it was a prison for him. In a long monologue, he addresses all the villains of the Alliance, which includes the Atraxi, Autons, Cybermen, Daleks, Judoon, Silurians, Slitheen family, Sontarans, Sycorax, Zygons, and more.
Unarmed, with just his voice, he makes all the spaceships stand still and listen to him, which depicted the influence he had on the universe and its beings. Using his confidence and authority in the face of violence was one of the bravest things that the Doctor could do, and he did it often. However, watching him stand up against hundreds of villains out to get him with nary a weapon is imprinted in fans' minds.
All Thirteen!
"The Day Of The Doctor" was one of the most ambitious crossover episodes in Doctor Who involving several Doctors. Fans were just delighted to see Ten, Eleven, the War Doctor, and even Rose meet with each other and compare notes to see what Ten did better than Eleven and vice versa.
In the episode, three Doctors together attempt to freeze Gallifrey forever in a moment in time to avoid it from being annihilated by the Daleks, but then every single Doctor appears to help. The moment builds up amazingly, especially when everyone realizes that it's not twelve, but thirteen Doctors flying towards Gallifrey in one victorious moment, each one being their unique selves and doing what they do best: saving worlds, but using all their combined powers of every regeneration.
The Time Lord Victorious
Ten wasn't always as abiding of the Laws of Time as his counterparts. Despite being stable most times, he lost control during "The Waters of Mars" where he couldn't bear to watch the deaths of people he could save because they were fixed points in time.
In a terrifyingly awesome moment, he makes audiences feel the full impact of the power he holds while he saves Adelaide and others despite that breaking the rules. In the end, he calls himself a winner — a Time Lord Victorious over the very concept of time and space. Being the holder of all that power, it's easy to see that the Doctor could go off the rails and lose his sense of benevolence to give rise to something more sinister. Ten sounded less like himself and more like the Master, and gave fans a taste of what a power-crazed Doctor could look like.
Calling Back The Atraxi
The introductory episode of Eleven was nothing short of iconic. In addition to his quirkiness with fish fingers and custard plus a penchant for bowties, audiences still got to see his defiant yet admirable side early on in "The Eleventh Hour".
After he makes the Atraxi leave with Prisoner Zero, he makes it a point to summon the aliens back to him to have a conversation — one where he makes it clear that planet Earth is protected by the Doctor, and that they shouldn't dare to set foot onto it ever again. To call a dangerous alien back after they had fled to reiterate that they had a formidable foe on Earth was a signature move of the Eleventh Doctor. This made audiences get a feel of what his run as the Doctor would be like: full of epic moments of bravery like this one.
The Unarmed Doctor
A lot of Twelve's authority came from a kind of quiet force and power within him, which made him much revered by almost every human, Time Lord, or alien in several universes. In "Hell Bent", fans got to see this first hand, as Rassilon's army recognized the Doctor from the war, mainly because he was unarmed, which is one of the Doctor's most respected habits.
As Rassilon asked for his squad to fire, they all intentionally missed a silent Doctor and then defected to his side as he stood silently without saying a word. It was a testament to the legacy that the Doctor had left behind for many centuries as a protector and a benefactor that he didn't even have to say a word to gather the Time Lord soldiers behind him. For that, it was a totally badass moment of Doctor Who.
Start Believing
The Thirteenth Doctor may be plagued by bad writing due to Doctor Who showrunner Chris Chibnall, but she still had some groundbreaking moments of looking extremely cool during her run. Without a TARDIS for a while, she eventually finds it on the planet Desolation in "The Ghost Monument" as part of an intergalactic race that had grand prizes.
After she gets her beloved and newly revamped space and time ship back, Thirteen turns to her fam and asks them if they want to go home. Upon facing their disbelief, she tells them to "start believing". Seeing Thirteen regain her confidence along with her TARDIS after feeling lost and off-balance for the initial few episodes was a relief. This made fans remember the might and influence that the Doctor has held, man or woman.
Do That Again
A rogue Dalek in "Resolution" gets the Thirteenth Doctor to show her badass side when it takes over an innocent civilian and threatens to kill her. As seen in previous situations, angering the Doctor only makes her more brutal, and that's what the Dalek did by laughing at her when she was trying to fix the problem.
After hearing the laugh, an infuriated Doctor pulls the Dalek into her ship by a bio tracking technology and tells it to laugh at her again, to her face if it had the guts to. The usually milder Thirteen showed her lethal side when faced with her biggest foe. Audiences loved seeing her go a bit rogue despite her usual quirky personality.