Theme in Yellow
The speaker opens the poem through the perspective of a pumpkin in autumn when it has a yellowish color to it and can be seen all over the hills. It then looks to have more of an orange/tawny color to it, presumably because it's grown and is waiting to be picked. When Halloween rolls around, children join hands around the pumpkin and sing ghost songs. So by now, the pumpkin is a jack-o-lantern with "terrible teeth," but the children know the pumpkin is only playing around and isn't really something to be frightened of.