Three short lines announce a loss in a strangely formal way. "No longer with us" is the language of obituaries, the phrase people use when someone has died. Here it is applied to a "giant metal toad," and that mismatch is where the poem gets both its humor and its feeling.
We don't learn what the toad was. It might be a sculpture, a piece of playground equipment, or something else entirely, and the poem doesn't say. Judging by the wording, the speaker treats it as a real presence that mattered, and that makes the loss feel oddly sincere rather than just silly.
The mood is quiet, deadpan, and a little wistful. The broken line breaks, with "metal" and "no" left hanging at the ends, make the statement feel hesitant, as if the speaker is pausing before saying something hard. It's a small farewell to something unlikely, and it asks us to take that seriously.