Vault of Challenges (1)

[128Up!]

I am an object, five characters strong.
Use these clues to figure me out, it shouldn't take long.

Myself in full swing, when all five are in place, is an item which shows numbers with its hands.
Behead me just once, and I pair with a key, I am picked by cheats throughout the lands.
Behead me once more, and science-fiction kicks in, as I become a villain with limbs of eight.
These three clues are enough to tell me my whole self, and as my whole self, I insist you're not late~

[Zorayda]

Better late than never
My brains ticks and tocks
You think that you're clever
But I know you're a clock.

[128Up!]

It is nice to see an attempt,
And you are without fault,
...I applaud you when I say...
You have opened the vault!