Crusading Knight

The color-hoser before the term existed: a four-mana white creature whose entire combat profile is leased from the opponent's commitment to black mana. Against a deck without Swamps it sits as a 2/2 with protection from black, which is to say it does nothing and dares the opponent to play the basics that would make it relevant. Against a mono-black or heavy-black opponent it balloons, gaining a static +1/+1 for every Swamp across the table, and the protection clause means that same opponent's targeted removal cannot answer the thing their own lands are feeding. That asymmetry is the design idea: a creature that grows in exact proportion to how heavily the opponent leans on black, turning the opponent's strongest deck into its best matchup. The drawback is real and load-bearing. You cannot reliably size the body when you build, because its dimensions live on someone else's battlefield, so it behaves like a sideboard answer wearing a maindeck threat's clothes. This is the protection-plus-pump tax in its purest form: a color-hoser that punishes one specific enemy and idles against everyone else, a shape the game has largely retired in favor of drawbacks the controller can plan around rather than ones the controller cannot. As an artifact of an era when swingy, opponent-dependent hosers were printed as creatures rather than sideboard spells, it captures a sharper, less forgiving idea of what a sideboard answer was allowed to be.