An unexpected attack from swarms of venomous wasps killed two American tourists, a father and his son, during a zip-lining trip in Laos. The attack occurred on October 15 but was publicly reported earlier this week.

Daniel Owen, 47, and his 15-year-old son Cooper were swarmed and stung more than 100 times while they were zip-lining at an eco-adventure resort near Luang Prabang on the Mekong River in Laos on Oct. 15, local authorities said.