You can use this card to return your opponent's monster to negate the battle. However be careful when targeting the opponent's center monster while its attacking, as it will allow them to attack with their Item.
Use this card to protect one of your monsters that is being attacked. This will also negate your opponent's attack, since it no longer has a target.
You can stop a Link Attack against one of your monsters with high defense, the remaining attacker(s) left will most likely be unable to destroy your monster, effectively stopping most of your opponent's attacks that turn.
You also can use this card to return your opponent's center monster during your turn before you attack.
If you use this card when Jackknife Dragon uses his search effect your opponent may search their deck but they cannot call anything because they cant place their Jackknife on top of anything causing them to waste 2 gauge.