The Riddle Game isn't played with a "mythical" creature - it's played with Gollum. We learn later that Gollum is actually Smeagol, and that he was once a Hobbit himself, from a time before they migrated to the Shire.
Gollum misunderstood him. Bilbo was saying 'I need more time.' Gollum heard 'time', which was the answer.
By 'the hobbit', I'm supposing you mean Bilbo Baggins in The Hobbit? If so, he faced Smaug the Great Dragon, King of the Lonely Mountain.
Bilbo Baggins is a hobbit from The Shire.
The dwarves are Bilbo's friends for most of the Hobbit.
Bilbo IS a Hobbit. Etymologically, a Hobbit is literally a "hole dweller" while Bilbo means "a short sword".
All of them help Bilbo in "The Hobbit"
Yes he is a hobbit. He is a relative to Frodo.
Bilbo Baggins
Bilbo Baggins was hired to be the burgler in the Hobbit.
bilbo baggins
Because Bilbo won it in his game of riddles with Gollum.
Bilbo was 50 years old in The Hobbit, which was considered middle aged for hobbits.