Whenever Hans Eriksson attacks, reveal the top card of your library. If it's a creature card, put it onto the battlefield tapped and attacking defending player or a planeswalker they control. Otherwise, put that card into your hand. When you put a creature card onto the battlefield this way, it fights Hans Eriksson.
The defending player is the player Hans Eriksson is attacking or the controller of the planeswalker Hans Eriksson is attacking.
Putting a creature card onto the battlefield this way causes a second reflexive triggered ability to trigger. Players may respond to this ability before it resolves.
If the creature card you put onto the battlefield isn’t on the battlefield or isn’t a creature as the reflexive triggered ability resolves, neither that creature nor Hans will deal or be dealt damage. The same is true if Hans isn’t on the battlefield or isn’t a creature at that time.