Amygdala is a Great One Boss in Bloodborne, and is found in the Nightmare Frontier. It's similar to the large enemies who attempt to grab the Hunter with portals, but lighter in color, and lacks the tentacles on its head.
From Wikipedia: "The amygdalae (singular: amygdala) are two almond-shaped groups of nuclei located deep and medially within the temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing of memory, decision-making, and emotional reactions, the amygdalae are considered part of the limbic system."
1. Amygdala (the boss) has an arm on the right side of its body that is always raised during the boss fight. In the palm of this arm's hand is a glowing eye shape, similar to the one on its chest area.
2. The Amygdala fought in the Nightmare Frontier does not have tentacles on its head like the amygdalae seen in Yharnam.
3. The eyes in Amygdala's head are not always visible.
4. The heads and arms of the Amygdala resemble the Garden of Eyes enemy, especially when the Amygdala eyes are visible.