goes blind because Willow mentions he "can't see anything." Xander becomes a literal "demon magnet."
You can find the full script and dialogue breakdown on Buffyverse Wiki . [S1E7] Something Blue
If you are looking for the specific text of the spell or the props used, here are the key details: goes blind because Willow mentions he "can't see anything
get engaged and begin planning a wedding (the source of the episode's title). Key Quotes & Sources: [S1E7] Something Blue