The names of the two creatures are spelled differently. The creatures in the lesson are Erklings, whereas the creature in the poem was THE Erlking. One word can be transformed into the other by transposing two adjacent letters - the k and the l - but this difference indicates an essential difference between these two creatures. The Erlking was the king of the elves, and in a single country there is usually a single king, whereas there are many Erklings in the Black Forest in Germany.
In the poem, the father and the son were …show more content…
But if the father had really seen and heard the Erlking, he wouldn't have waited until it had touched his son before speeding up his horse. Evidently the Erlking was invisible and inaudible to adults. But Erklings are not invisible or inaudible to adults; adults simply know better than to be lured by their cackling.
When the Erlking in the poem did touch the boy, it didn't drag the him off his horse and then eat him, whereas Erklings do eat the children they catch. Instead, it was satisfied with having touched the boy, thus ensuring that the boy would soon die, which he did while still in his father's arms.
Given all these differences between the Erlking in the poem and the Erklings in the lesson, I think it is safe to say that they are entirely different creatures: the former is a figment of some Muggles' imagination and the latter is a magical creature with which Muggles have never come in