Well, that's a bit exaggerated, but spiders will pay people visits at night occasionally, sometimes biting them and feeding on their blood. Reactions/wounds caused by spiders and their bites are rarely severe, however, as this most commonly occurs with house spiders (non-venomous, usually very small, and basically harmless). In some cases a person's skin around a bite may become slightly red and irritable, but most bites go completely unnoticed.
Is the myth about people swallowing an average of so many spiders at night true, btw?