The rule of thumb here is you generally want to spend less killing something than your opponent spent making it
Its certainly the most tempting, because Hydras can be loads of fun, and having them be bigger for the same amount of mana is even more fun
If your deck would like Altar's Reap, Keskit can do a similar job every turn
You can only get the Japanese variants from collector boosters if youre opening a product of any other language
As a sorcery, you may pay the mana cost of a locked door to unlock it.) When you unlock this door, search your library for a basic land card, put it onto the battlefield tapped, then shuffle
If you already have a Skullclamp on the battlefield or in your hand, other good targets for these tutors would be your token generators or one of your sacrifice outlets