Thought Collapse

Cancel with a rider, and the rider does something the pure-tempo counterspell never bothered with: it grinds three cards off the countered spell's controller while it protects your position. The extra pip over the two-mana template pays for that, but note what the design refuses to do: both halves fire together, always, with no choice offered. You cannot spend the counter cheaply because the mill is often irrelevant, and you cannot cash in the mill without a spell to answer. The two effects are welded, and that welding is the card's whole texture. In a graveyard-neutral matchup those three cards are a footnote, a trivial coda to the counter that does the real work. Against a deck that wants nothing to happen to its library (a control shell thinning toward a single win condition, a deck stocked with cards it plans to draw twice, anything where the top three cards carry weight) the attrition starts to bite, and the counterspell doubles as library damage. It belongs to the branch of countermagic that declines to be clean tempo, the counter-plus-a-body and counter-plus-a-card lineage, but here the second effect attacks the resource most permission decks ignore entirely. Whether that attached three-card bite is a real gain or an inert coda depends entirely on what you are pointing it at, which makes it a sharper deckbuilding decision than the flat rate lets on.