Sacred head of the Vault Dweller
Damn tourists...”— The head of the Vault Dweller
The Talking Head is a Fallout 2 special encounter. You can "meet" him in the Wastelands near Arroyo (or NCR, maybe anywhere in the map), and he is actually a talking version of the big stone head of Vault Dweller in the Arroyo village center. If you talk to him and tell him you are The Chosen One, he disagrees and begins an argument back and forth that lasts until nightfall. He will then concede that you have proven yourself to be The Chosen One and give you a monument chunk as a reward.
If you happen to be a kleptomaniac, and steal from the big stone head, you'll find 4 or so more monument chunks as an award. However, you won't get very far with it, as the Vault Dweller's head dishes out a world of hurt, damaging you at about 14,000 HP, and melting you.