Theory:

Name of the poem: Macavity: The Mystery Cat
Name of the poet: T. S. Eliot
 
Macavity’s a Mystery Cat: he’s called the Hidden Paw —
For he’s the master criminal who can defy the Law.
He’s the bafflement of Scotland Yard, the Flying Squad’s despair:
For when they reach the scene of crime — Macavity’s not there!
 
Macavity, Macavity, there’s no one like Macavity,
He’s broken every human law, he breaks the law of gravity.
His powers of levitation would make a fakir stare,
And when you reach the scene of crime — Macavity’s not there!
You may seek him in the basement, you may look up in the air —
But I tell you once and once again, Macavity’s not there!

Macavity’s a ginger cat, he’s very tall and thin;
You would know him if you saw him, for his eyes are sunken in.
His brow is deeply lined with thought, his head is highly domed;
His coat is dusty from neglect, his whiskers are uncombed.
He sways his head from side to side, with movements like a snake;
And when you think he’s half asleep, he’s always wide awake.

Macavity, Macavity, there’s no one like Macavity,
For he’s a fiend in feline shape, a monster of depravity.
You may meet him in a by-street, you may see him in the square —
But when a crime’s discovered, then Macavity’s not there!
Reference:
National Council of Educational Research and Training (2008). Honeydew. Macavity: The Mystery Cat - T. S. Eliot (pp. 50-51). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.