What do you call giant sleeping Lizards?

I wear a coat of emerald green, With tiny veins like rivers seen. I dance with fairies in the breeze, And whisper secrets to the trees. I hold a drop of morning’s dew, A tiny mirror of the sky so blue. When autumn comes, I trade my hue, For amber, gold, and crimson too. What am I, a little spell the forest grew?

Trim, paint, and bedazzle me on your phalanges if you like. Integral for constructing, securing, and building just right. But be wary, stepping on a rusty me will result in a painful lockjaw. And to put me in a coffin? Well that’s the very final straw.

The type of cheese that doesn’t belong to you

There are four things I could be, An armless chair found at a bar, The growing stump of plant or tree, A sample from the Bristol Chart, Or finally, a decoy bird - would a pigeon be too absurd?