True Strike 2.0

As a bonus action, steady yourself to strike true. You pour all your focus into readying yourself and tensing yourself against your weapon for one massive blow. 

Until your turn you are immune to effects which would cause you to move against your will, and on your next turn, if your first weapon attack hits, it is automatically a critical hit.

The focus required to land this strike means that once you have cast this cantrip you cannot move or take any actions or reactions until you have attempted your True Strike. (I.e., casting this cantrip ends your turn, and then the first thing you do on your next turn is a weapon attack, which, if it hits, is a critical hit).