Note: I will be primarily discussing these card's implications in non-rotating formats, so please keep that in mind
Pretty much all the best MTG dragons have enormous stat blocks and flying, so they can pretty easily pressure an opponent's life total on their own
Bulbasaur is just hanging out near the bushes looking confused
Set Number 236 Language Franais Legal Formats Commander, Legacy, Modern, Vintage Not Legal Formats Alchemy, Brawl, Competitive Brawl, Historic, Pauper, Pioneer, Standard, Timeless Rulings (8/1/2008) Casting a card by using its retrace ability works just like casting any other spell, with two exceptions: You're casting it from your graveyard rather than your hand, and you must discard a land card in addition to any other costs
Bristling Hydra: [Category 2] ETB yield is 3 Energy for 4 mana, then you can spend 3 Energy to place a +1/+1 on this creature and give it end of turn Hexproof
Previously, in cases where a card's mana value differed from the resulting spell, such as with some modal double-faced cards or cards with an Adventure, you could cast a spell with a higher mana value than the exiled card