Larry's "Monster" is a speaker's attempt to untangle what life and death really mean, and the poem keeps doubling back on itself to do it. Almost every line begins with "they say," as if the speaker is repeating things they've been told and not quite trusting them. Then comes a string of "or is it" flips: you die when you live, or you live when you die; death is an ending, or it's being "cut free to fly."
The turn comes when the speaker admits that "monsters don't exist" is "a lie." Instead of something to fear, the monster is imagined as living in our bones, tied to the soul even after death. The speaker wonders whether it might be the very thing that cut the string and let us fly, and that showed us what light is.
The mood is thoughtful, uncertain, and quietly hopeful. The final line suggests that what we look up to as death may actually be life.