2020-06-23 : Hexproof from black means that Garruk's Harbinger can't be the target of black spells your opponents control or abilities your opponents control of black sources.

2020-06-23 : If Garruk's Harbinger deals damage to a planeswalker greater than their loyalty or to a player greater than their life total, you look at a number of cards equal to that full amount of damage dealt, not just that loyalty or life total.