Those!

 is a Fallout 3 quest. It is also an Xbox 360 achievement.

A lost, small boy called Bryan Wilks asks you to help him find his father, who seems to be trapped in Springvale, while he takes refuge in a diner.

Find Bryan Wilks's father
The boy and his dad were attacked by Giant Ants. The father can be later found dead, killed by the ants. You can loot a Chinese Assault Rifle off his body.