Four short lines are enough for Dave Bonta's speaker to make a boast and quietly take it back. "I am plausible in my art" sounds like a modest credential, but the word doing the work is "plausible". Nobody dreams of being called plausible. It means believable, convincing on the surface, which is not the same as true or good. The word comes from a Latin root linked to applause, so it once suggested something worth clapping for, and it has since cooled into something that merely gets past inspection. The speaker can persuade an audience and seems to know that persuading is not the same as being the real thing. The poem never says what the "art" is, so it could be writing, painting or any craft. What matters is the gap between seeming and being.
Then comes the turn: "but I rust." After a seven-syllable opening line, this one is three blunt words, and the "but" shuts the door on the self-praise. Rust is a metaphor from metal. It pictures the speaker as a made thing, a tool or a statue, once bright and now slowly flaking. It also hints at cause, because tools in constant use stay clean and rust takes hold in neglect. Everyday speech knows this too, since we call someone "rusty" when their skills have slipped from lack of practice. Notice, too, that the verb has no excuse attached. It isn't "my art rusts" but "I rust". The decay has moved from the work to the person who makes it.
The second stanza reads like an explanation, though the poem never says "because". "I pass so much time" can mean idling, whiling hours away, but "pass" also echoes "plausible". One can pass for something one is not, and the speaker may be passing time and passing as an artist in the same breath. Then "full of sleep" gives an oddly ambiguous ending. Is the speaker full of sleep, like a vessel filled to the brim? Or is the time itself full of it? The syntax allows both. People are usually "full of" energy, ideas or themselves. Here the container holds the opposite of making.
The form supports all this. Two couplets, no rhyme, no punctuation, and the only capital is the pronoun "I". Line lengths run roughly seven, three, five, three syllables, a long line followed by a short drop, twice, so each stanza ends in a small deflation. "Art" and "rust" share their r and t without rhyming, an echo that never quite closes. The sounds do their own work as well. The soft s runs through "plausible", "rust", "pass", "so" and "sleep" like a hush, and the long vowels of "time" and "sleep" slow the ending until it seems to drift off. With no full stop, the poem trails away rather than finishing, which suits a speaker caught in drowsiness.
The title, "Mutable", adds a final irony. It means able to change, and it can also mean fickle. Yet the two changes the poem names are not ones the speaker chooses. Rust and sleep are things that happen to you. They are also opposites in one respect: rust is a one-way road, while sleep is something you wake from. The poem does not say which of the two describes the speaker, and the title leaves room for hope. A self that can rust can, in principle, also be polished or woken.
What makes the poem worth a student's time is how much it does with so little. It refuses the glamorous picture of the artist as tireless and inspired, and offers instead a candid, slightly embarrassed self-portrait. The poem is itself a small piece of art, and its honesty about its maker's doubts is what lifts it beyond merely plausible.