The boss as seen in the NES
Shadow Beast Entrance was a type of immobile emplacement located just outside the first enemy base. It consisted of a alien-like head above the entrance into the base and was armed with two cannons embedded in the alien's shoulders that shoot out explosives at the ground in an arc. These same cannons are the weak spot of this alien boss and once the cannons are destroyed, the door will exploded and be open, enabling the player to continue on inside the second enemy base. It has appeared in the original Contra, Contra 4, and its remake.
Contra: Legacy of War
He appears as the boss of level 3: River of Destruction. in here, both of its arms each have individual attacks. The Left Beast Arm periodically spits fireballs at the player, while the Right Beast Arm periodically spits a short, homing flame burst. Once both arms are destroyed, the alien’s head begins attacking. It periodically spits a large ring of projectiles that break into 2 smaller ones; these smaller ones fly towards the player. The weakness of this boss is its Pulsing Core, which becomes vulnerable after the 2 arms are destroyed.
The boss as seen in the PS1 game Contra: Legacy of War.