Tankensteins are some of the toughest enemies you'll face on the Zombie Island of Dr. Ned. Always encountered as a Badass version, they are similar to Suicide Zombies in that they carry explosive barrels on their backs. Unlike suicide zombies, they are not killed when the barrel is detonated, but are merely damaged and stunned for a short time.
Throwing explosive barrels
Charging / Ramming
Like a fuel tank, the barrel takes damage from the number of successful hits and not damage taken. After the barrel explodes and the Tankenstein is stunned, aim for the head.
Shock damage heals a wounded Tankenstein for large amounts of health, so avoid its use in any form. Lilith's Radiance is especially pernicious, as this skill will continually heal the Tankenstein until its effect ends.
A thrown explosive barrel will stun the Vault Hunter for 2 seconds if it connects. Shoot the barrel in midair to detonate it prematurely.
Killing a Tankenstein with a critical headshot does not produce a zombie brain.
Detonating the barrel on Tankenstein's back does not stop the explosive barrel attacks, and only serves to stun.
Tankensteins are large, and will occasionally get stuck in terrain features such as doorways.
The name Tankenstein is a reference to Mary Shelley's character known as "Frankenstein's monster", simply and much more commonly known as Frankenstein. Tankenstein's healing effect when shocked may be inspired by how Frankenstein was reanimated with lightning.
It appears that Tankenstein's left foot is broken or mismatched.