“Most badass scene from any anime character”
It’s hard to decide. In G Gundam, Master Asia fights mecha with a piece of cloth; in Gurren Lagann, Lordgenome not only fought Lagann with his bare hands but was also able to give a dying speech with a giant hole where his heart and lungs should be (and in the same fight, Simon puts that hole there with what is essentially his keys); in Bleach, Kenpachi Zaraki exists.
This is manga-only, but not much else can top it; in Shin Mazinger Zero, Kouji Kabuto’s reaction to his arm being severed (and what happens to Sayaka in that timeline) is to throw it as an improvised human-scale Rocket Punch!
But I think I’ve got to give it to Dragon Ball Z’s Vegito; silly badassery is still badassery, and well:
Through sheer determination and/or power, he kept fighting (and winning!) after being turned into a piece of candy. After that he went on to let himself be absorbed on purpose so he could (and did) free Buu’s victims from the inside, a case of supreme confidence actually being justified.