Bahorel doesn't wait for Harry to climb any higher before sticking his arm into the gap between books and waving wildly about.

A moment later a swarm of what would be spiders, if they weren't also crumpled balls of paper, roils out of the gap and over the shelves, some climbing higher and some dropping in a soft papery rain down the shelves.

Bahorel pulls out an arm now wound about with shredded paper rather than cobwebs, and shakes himself to dislodge a last few paper spiders before leaning over to look in the gap. "They come back if no one comes this way for a few weeks. Sometimes it's the only way I'm sure how long I've been away-- ah but looks like they've cleared out now. Come on!"

He slides through without worrying if Harry can manage the same. Harry's smaller than him, after all.