Barkhide Troll enters the battlefield with a +1/+1 counter on it.
{1}, Remove a +1/+1 counter from Barkhide Troll: Barkhide Troll gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)
Because damage remains marked on a creature until it’s removed as the turn ends, nonlethal damage dealt to Barkhide Troll may become lethal if you activate its last ability during that turn.