Your skill is halved when a task is harder than average, which is considered a difficult skill check.
Difficult Actions Fighting an opponent you can’t see, climbing a smooth surface, or remembering obscure scientific minutiae are all Difficult tasks. To determine the skill rating or characteristicA hero's base physical and mental abilities. More rating for a Difficult action, divide the appropriate skill or characteristicA hero's base physical and mental abilities. More roll in half (round up).