system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 Can someone explain about COBALT element and how harmful it is? I was reading about a COBALT bomb which some says is a myth but if it is true then it is way deadlier than H-Bomb.
gpt
A traditional nuclear bomb, like the H Bomb, has a core of nuclear material that as it goes thru fusion or fission, it produces a large explosion.  The intent is to try to use up as much of that material as possible to produce the biggest explosion, but it doesn't work out that way.  As a result, not an of the nuclear material gets used up and is then scattered in the debris of the explosion.  This radioactive material becomes the nuclear fall out that becomes the next deadliest part of a nuclear weapon.  It's not intentional, basically a side effect of the design.

Cobalt bombs (not the tri-cobalt of science fiction) is designed to intentionally increase the amount of fallout by dispersing a radioactive form of cobalt over a much greater area.  Not only does it produce more radioactive fallout, but the cobalt isotope lasts much longer, not only affecting humans but making any crops unusable and poisoning livestock and wildlife with radiation.