Silver Raven

In a small silver box, a silver raven figurine is nestled in a velvet cushion. The lid contains an inscription:

O my master weak and weary, stumbling ‘round in dungeons dreary
If a guide you do desire, cast my form upon the floor
Half a day I’ll help your scheming, then I must return to dreaming
When twice you glimpse the dawn’s light streaming, I’ll heed your summons - not before
Once my duty is completed, should I needs return before
Simply speak this: Nevermore