Desertion

The blue color pie's answer to a question Treachery and Control Magic ask in slower terms: why steal a permanent after it resolves when you can intercept it on the stack? The design trick is that it folds two effects into one window. The counter is unconditional, so against a land destruction spell or a planeswalker it is a flat five-mana Cancel; against an artifact or creature spell it converts the counter into theft, sending the card to your side of the battlefield rather than the graveyard. That conditional upgrade is what makes the rate make sense. Five mana at instant speed is steep for a counterspell, but the payoff is that you are not trading one-for-one: you deny the spell and gain the body in a single resolution, and the opponent never gets the enters-the-battlefield trigger or the chance to respond as they would to a Control Magic enchanting their creature later. The friction is the timing requirement: you have to hold up five mana and catch the spell on the stack, which means reading the opponent's turn correctly rather than reacting to a resolved threat. It is a counterspell that asks you to know what is coming, and rewards you with the best version of the steal effect when you do.