Complex sentence: This ability can be used to sneak up on the survivors, however the Wraith must uncloak itself to attack, which slows his movement and rings a loud bell which signals to the survivors that the Wraith is either cloaking or uncloaking itself.
Split into simpler sentences: This ability can be used to sneak up on the survivors, however the Wraith must uncloak itself to attack. A bell chiming signals to the survivors that the Wraith is either cloaking or uncloaking itself.