The rarest card in the first edition Jungle set is the Ivy Pikachu, which was supposedly included accidentally in the set
The high prices mainly come from premium reprints of good cards in Marvel Universe (MAR), or rare and mythic Spider-Man Eternal (SPE) cards, and all of them are driven by scarcity
Once the end of a dungeon is reached, the card will offer a reward for completion, including the chance to draw additional cards, create token creatures or cast a card without paying its cost
Erebos, Bleak-Hearted is a whole other thing
cards to pay for them, and will attack Leaders and other Characters using their own cards, in the hope of being strong enough to make the opponent draw cards from their Life area until they have none left to draw
Skullclamp is also perfect for green because you tend to run a multitude of 1-toughness critters that will draw you two cards per equip