Meanings of mad challenge in English

At this mad challenge of mine silence closed down like a shutting trap.

The innocent blue eyes look at me in mad challenge.

And yet, Felix d'Aubremel, one of the bright applauded heroes of those orgies, seemed in no mood to answer their mad challenge.

This was the torture in his soul that had led him to many a mad challenge of Death, who always scorned his defiance.

Deep-water Peter felt from the first that he could not dwell for long on the mysteries of that island without meeting little Rackby's mad challenge.