Gargantuan should be correct
Answer. "tis some visitor." The reader feels suspense as to whom this visitor may be.
Explanation::He tries to calm himself down, telling himself that "tis some visitor" who has dropped by unexpectedly. But who is this visitor?
(sorry this is so late!)
The reason why I believe that the author Maya Angelou included this passage is because she wanted to explain to us her emotions about the connection she had.