Experience reprints from Magic's history in the art and story of Final Fantasy Commander Decks
Once per turn, you can flash back an instant or sorcery, effectively doubling up on your most critical combo pieces
The Commander Rules Committee has stated that this is because it is very hard to kill more than a single player with poison, especially because your opponents likely are not piling on with their own infect creatures
When you sacrifice it to Skirk Prospector, it returns with a -1/-1 counter, but this cancels out against the +1/+1 counter provided by Metallic Mimic or First Day of Class
Its generally better to buy individual booster boxes over cases
"Pay 1 life, Sacrifice this land: Search your library for a [basic land type(s)] card, put it onto the battlefield, then shuffle." A fetch land in MTG is a land that lets you sacrifice it to search your library for a land with the specified land type(s) and put that land onto the battlefield