Truth be told I have defeated people with PK Thunder from Ness many times. Varies on angle and where the opponent is. They can bump into the stage corner and into oblivion. This is easiest to do against people who like to go low on the stage to recover (Ike is the easiest I can do this against so far).
As for dodging, spinning it always lands the tail at least if not the head included but at this point makes it harder to kill them with (not like it matters, they take damage + if they bounce back onto the stage very close to you you can hit them again with something quick)
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