Everything on the stack gets exiled, mana pools empty, "until end of turn" and "this turn" effects end, and damage wears off
Blink is a pretty 1D mechanic that punishes decks using the removal we all seem intent on nerfing already
Suddenly, your vault of resources is a lethal robot army
Was that about what you expected or did it come as a surprise
At one time, there were two separate ban lists, one that tracked cards that were banned from the Commander format in general, and another listing specific creatures that were banned as a commander but ones you could still play in your 99
If the target creature is an illegal target by the time Chain Assassination tries to resolve, it won't resolve and none of its effects will happen