A possessed mob carries a class template: attributes, talents and actives. They use that class’s kit — dashes, zones, shields and forms.
Possessed Slasher and Duelist do not deal dash damage through walls or from arbitrary range. They close in with line of sight first, then hit in reach.
In singleplayer, when the menu pause stretches the integrated-server tick interval past 200 ms, possessed timers shift by the pause duration together with the player’s cooldowns.
The direwolf is the exception: possession never applies to it. Details — Direwolf.