If it's the fourth or subsequent time the first ability has resolved in a turn, nothing happens
If your deck has some number of fetchlands like Misty Rainforest, Evolving Wilds, Myriad Landscape, or Blighted Woodland, you should strongly consider Erinis for your deck
This usually happens when your opponent's main force is sufficiently bloodied, crippled or damaged enough that, while they can continue to fight, their effectiveness is severely reduced and the best they can hope for is a Pyrrhic Victory
The card does pair exceptionally well with Deadly Dispute-esque effects, which could allow it to see some unexpected play in Pauper
This means that the before this product existed, Vampire Koala and Vampire Orchis had card interactions with Vampire Vamp in English-speaking territories that it would not have in Japan
Pokemon had less HP and weaker Moves never managed to disappoint in their depictions