Web Attack: Fake AV Download 2 and Web Attack: Malacious Website Accessed 2 blocked

Hello. Earlier today, we were on the internet and 2 items were blocked by Norton. The 2 were called Web Attack: Fake AV Download 2 and Web Attack: Malacious Website Accessed 2. My brother thinks it was due to a site connected to wikia.com on account of the fact that the site crashed on him. What are these threats and what could've caused them? Thanks.