Rev 17: the wave carries monsters as it carries wizards

Stone to Water's wave (and every waterwall collapse) washed wizards
back and crushed them against the maze — while a skeleton in the
same water stood dry. The wave only knew creatures well enough to
drown fire imps. From rev 17 it carries them all: washed back along
the surge, one point of crush per space the maze refuses, fire imps
still destroyed outright. Earlier ledgers keep their dry monsters
and replay so.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/engine/test/creatures.test.ts

@@ -550,3 +550,42 @@ describe("creatures walk open doorways", () => {
     throw new Error("setup: seed 42 grew a maze with no doors");
   });
 });
+
+describe("the wave carries monsters (rules rev 17)", () => {
+  it("a cornered skeleton takes the waterwall crush", () => {
+    let { state } = createGame({ playerIds: ["a", "b"], seed: 42, sets: ["basic", "expansion1"], deckRev: 17 });
+    state = toRound2(state);
+    const caster = activePlayer(state);
+    // A skeleton pinned against solid stone, one square from the wave's edge.
+    const view = boardView(state);
+    for (const [key, edge] of Object.entries(view.edges)) {
+      if (edge !== "wall") continue;
+      const [kind, coords] = key.split(":") as [string, string];
+      if (kind !== "H") continue;
+      const [x, y] = coords.split(",").map(Number) as [number, number];
+      // Wave from this wall southward washes the square below.
+      const below = { x, y: y + 1 };
+      if (!view.cells[cellKey(below)]) continue;
+      state.creatures.push({
+        id: "sk1", kind: "skeleton", controllerId: caster.id,
+        position: { ...below }, damage: 0, maxDamage: 4, movesPerTurn: 3,
+        movementUsed: 0, attackUsed: false, justCreated: false,
+        wallPassesPerTurn: 0, wallPassUsed: 0, scorchedThisTurn: [],
+      });
+      // Pin it: stone directly south of it.
+      state.squareContents[cellKey({ x, y: y + 2 })] = { kind: "stone", damage: 0, createdBy: caster.id };
+      caster.position = { x, y };
+      const stw = giveCard(state, caster.id, "stone-to-water");
+      const r = applyCommand(state, caster.id, {
+        type: "cast", instanceId: stw.instanceId,
+        target: { kind: "edge", cell: { x, y }, side: "S" },
+      });
+      if (!r.ok) throw new Error(r.error);
+      const sk = r.state.creatures.find((c) => c.id === "sk1");
+      // Washed against the stone: it took crush damage (or died of it).
+      if (sk) expect(sk.damage).toBeGreaterThan(0);
+      return;
+    }
+    throw new Error("setup: no horizontal wall with a floor below");
+  });
+});