It's better than Opt in a non-graveyard sensitive deck, but in one that cares about the graveyard
Regardless, you wont have that kind of luck if you try to sell whatever random lands you have lying around your house from old drafts and collection buys
Gunk Slug is a neat design thats so frustrating to play against (I think its based on custom cards once played at a convention by Richard Garfield, though it mightve been Rosewater)
Notably, both the original and this Halloween reprint are offered as holofoil cards
To get an overview and refresher of the set's mechanics, check out our mechanics article
The rarest cards in a booster box are typically Special Illustration Rares or Alternate Arts. These feature unique full-bleed artwork and appear much less frequently than standard rare or holographic cards, often showing up only once in every few boxes