Spontaneous elemental prosthetic, (usually) to replace lost limbs

[u/RagingRider]

1. Bayle (The Elden Ring: Shadow of the Erdtree): entering his second phase, he grow a fresh set of red lightning wings to fly, and occasionally creates red lightning claws to swipe with, similar to Ancient Dragons.

2. Heimdall (God of War: Ragnarok): likewise, in his second phase, Heimdall creates a bifrost arm after Kratos blows up his original.

3. Ming-Hua (Avatar: Legend of Korra): born WITHOUT arms, she developed her own waterbending fighting style, but she's almost never seen without a pair of water tentacles.

[u/Cold_Hour]

I don't have a good example right now but Bayle summoning those wings has got to be some of the hypest shit ever. Love that fight so much.

https://giphy.com/gifs/Vu0Cpbl5p0rgY2HXzR

[u/danfenlon]

Finn manifested an arm made of psychics energy

[u/RagingRider]

One for the road: Seras (Hellsing; Ultimate)

After getting her arm ripped off by Zorin, she drinks her love interest Pip's blood, becoming a full vampire, evident by the shadowy substance that only Alucard has demonstrated before.

[u/Stunning_Box0003]

Rhaegar’s magical armor is a perfect example of this trope. Epic!

[u/iamamotherclucker]

Kuzan, aka former admiral Aokiji (One Piece)

After a fight with his former colleague Akainu left him short one leg, he used his devil fruit power, the Ice-Ice Fruit, to make a leg out of ice

[u/Polus-Ponos]

Endeavor 's fire arm

[u/jardanovic]

Shazam's lightning leg in Justice League Dark: Apokolips War