The second thing you need to know is that he will absolutely win you games, and people will often be perfectly fine losing to him
The tournament wasnt large, but it was full of stock decks from what I saw: Mono-Red, Green Black, Green White, a couple Teferi, a Mono-Blue player, etc
Search its owners graveyard, hand, and library for all cards with the same name as that card and exile them
In Pioneer, Underworld Breach saw heavy play in Lotus Field Combo as it made the strategy unfair and consistent
Even a tiny deviation in MTG card dimensions can disqualify you from a tournament or spell the difference between hundreds of dollars in resale value