Talk:Infinite Armament, Dangerous Cradle/@comment-26287946-20150601204237/@comment-4764137-20150602001353

Okay, here's the thing. Before the skill can be resolved, you must have a target. This is why call costs or cast costs can be used as targets for graveyard effects, but Return to the Underworld's gauge can't, and I'll explain how.

When a card is played from hand onto the field, the process is like this:  1. Declare the call/cast. 2.  Pay the call/cast cost. 3.  The opponent is given a chance to respond. 4.  The card enters the field/spell resolves. 5.  The card's on-call skill activates and resolves separately.

This is much different from an effect currently on the field which goes like this:  1. Declare the activation of the skill. 2.  Pay the cost. 3.  The opponent is given a chance to respond. 4.  The effect resolves.

Note that the difference here is that the skill that activates to target a card in the graveyard which can use gauge is a separate resolution process. Because Return to the Underworld does not start a separate process of resolution, the gauge it uses as a cost cannot be chosen, as its entry to the drop zone is too late to be a target. When you declare the activation of the skill is when you must have and choose a target. Therefore, a card such as Salvation Eir (which calls a card from the drop zone when it's called) can use a gauge paid for its call because the card's entry into the field was resolved, and now a new resolution is beginning after the gauge has entered the drop zone. Return to the Underworld starts resolving its call from the grave by choosing a target, then paying a gauge.