Neville had somehow managed to melt Seamus's cauldron into a twisted blob, and their potion was seeping across the stone floor, burning holes in people's shoes.
(Harry Potter and the Sorcerer's Stone)
There is a tricky word, holes, after burning. If holes is the object of burning, it’s semantically somewhat strange. If not, holes seems to be the result of burning. How can I understand the sentence?
The potion is very acidic, and reacts when contacting people's clothing. When acid melts through something and destroys it, we can refer to that as burning holes in something. I suppose technically nothing is being burned (or maybe it is, I suppose that's a chemistry question!) but the acid is "eating" through the material of their shoes and leaving holes behind. So burning holes is an acceptable way to describe what the potion is doing to their shoes.
From The Free Dictionary, two definitions which support the acid can burn aspect as well as the idea that holes can be burnt:
burn v.tr.
3) To damage or injure by fire, heat, radiation, electricity, or a caustic agent: burned the toast; burned my skin with the acid.
5. a. To make or produce by fire or heat: burn a hole in the rug.
I believe that in this sentence, "holes" is not the object of "burning". Instead, "burning" is used as a linking verb, and the noun phrase "holes in people's shoes" is the subject complement that completes the predicate.
Thus, the holes are not themselves on fire, but are created through the act of burning.
