A couple other borderless cards have also been selling for hundreds of dollars
Notorious TeamTron member, Henrik Has-Never-Been-Defeated-In-Old-School-Magic-In-Denmark Storm and I, tried to boil down a definition, but the closest we ever got was something along the lines of: A synergy between two or more cards, that is easily disruptable . I dont think that is very precise nor a very useful definition, because by this definition you will open a way too broad aspect of the game to being combo
Because the creature token has the triggered ability of dealing one damage to any target when it dies, I call it a Ping Devil
This makes Miraidon a solid pick for early pressure, keeping your opponent on edge
Figuring out how to properly adjust them takes math
Cards that Synergize with Sheoldred, the Apocalypse: Forces all players to draw seven cards, resulting in significant life loss for opponents while refilling your hand