The 10 Best Horns In The Animal World: The Definitive List - Modern Farmer
The peculiar dinosaurs of Laramidia: weird horns and more - CSMonitor.com
Polycerate - Wikipedia
Bizarre Horns of the Animal Kingdom
Just a weird phenomenon - the way insects (I guess termites?) are eating the outer part of these horns and leaving strange protruding structures - bonus if you can guess the location! :
The 10 Best Horns In The Animal World: The Definitive List - Modern Farmer