Please HELP. WHAT IS THIS?

[sidech]

No regular vet, please. They know nothing about birds. You need an avian vet.

[Saerphe]

Taking the bird out of his cage when it screams will just reinforce the screaming. Try ignoring it when it screams, and rewarding it when it plays quietly. You won't be able to eliminate the screaming entirely (especially from a very vocal bird like a Nanday conure), but you can establish more appropriate contact calls and alternate methods to get your attention.

I also recommend Michael's training blog.