Dragon's teeth (fortification)

Dragon's teeth are a foundational defense against an attacking ground force, and they are primarily considered a counter-tank measure. They can be of various sizes, shapes, materials, and arrangements.

The most recognizable are the square pyramidal reinforced concrete types. Many of these blocks are grouped together to form a single large obstacle. The rows of spiked concrete protrusions are meant to resemble "dragon's teeth," thus the name.

They are also referred to as "tank traps."