Fix Scythecat Cub

crates/engine/src/game/effects/counters.rs

@@ -1977,6 +1977,23 @@ fn resolve_defined_or_targets(
             .collect();
     }
 
+    // CR 608.2c: A `ParentTarget` in a chained counter effect refers to the
+    // object chosen by the parent instruction. Prefer that propagated object
+    // target over the triggering event context; for a landfall trigger, the
+    // latter is the entering land rather than the creature chosen by the
+    // player. The object guard deliberately excludes the chooser-only target
+    // bookkeeping used by `ChooseOneOf` branches above.
+    if matches!(target_spec, Some(TargetFilter::ParentTarget)) && has_object_target {
+        return ability
+            .live_object_targets(state)
+            .into_iter()
+            .filter_map(|target| match target {
+                TargetRef::Object(id) => Some(id),
+                TargetRef::Player(_) => None,
+            })
+            .collect();
+    }
+
     if let Some(filter) = target_spec {
         let event_targets =
             crate::game::targeting::resolve_event_context_targets(state, filter, ability.source_id);

crates/engine/tests/integration/main.rs

@@ -896,6 +896,7 @@ mod scarab_god_regression;
 mod scholarship_sponsor;
 mod screaming_nemesis_combat_damage_multi_trigger;
 mod screaming_nemesis_life_lock;
+mod scythecat_cub_second_resolution;
 mod search_delivery_observer_dedup;
 mod season_points_budget_modal;
 mod seasoned_dungeoneer_initiative_room_trigger;

crates/engine/tests/integration/scythecat_cub_second_resolution.rs

@@ -0,0 +1,96 @@
+//! Scythecat Cub doubles the counters placed by its second landfall resolution.
+
+use engine::game::scenario::{GameScenario, P0};
+use engine::types::ability::TargetRef;
+use engine::types::actions::GameAction;
+use engine::types::counter::CounterType;
+use engine::types::game_state::WaitingFor;
+use engine::types::phase::Phase;
+
+const SCYTHECAT_CUB_ORACLE: &str = "Trample\n\
+Landfall — Whenever a land you control enters, put a +1/+1 counter on target creature you control. If this is the second time this ability has resolved this turn, double the number of +1/+1 counters on that creature instead.";
+
+fn resolve_cub_landfall(
+    runner: &mut engine::game::scenario::GameRunner,
+    land_id: engine::types::identifiers::ObjectId,
+    target_id: engine::types::identifiers::ObjectId,
+) {
+    let card_id = runner.state().objects[&land_id].card_id;
+    runner
+        .act(GameAction::PlayLand {
+            object_id: land_id,
+            card_id,
+        })
+        .expect("land should be playable");
+
+    match &runner.state().waiting_for {
+        WaitingFor::TriggerTargetSelection { target_slots, .. } => {
+            assert!(
+                target_slots[0]
+                    .legal_targets
+                    .iter()
+                    .any(|target| matches!(target, TargetRef::Object(id) if *id == target_id)),
+                "Lotus Cobra must be a legal Scythecat Cub target"
+            );
+        }
+        other => panic!("expected Scythecat Cub target selection, got {other:?}"),
+    }
+
+    runner
+        .act(GameAction::ChooseTarget {
+            target: Some(TargetRef::Object(target_id)),
+        })
+        .expect("Lotus Cobra should be selectable");
+    runner.advance_until_stack_empty();
+}
+
+#[test]
+fn scythecat_cub_doubles_counters_on_second_landfall_resolution() {
+    let mut scenario = GameScenario::new();
+    scenario.at_phase(Phase::PreCombatMain);
+
+    let cub_id = scenario
+        .add_creature_from_oracle(P0, "Scythecat Cub", 2, 2, SCYTHECAT_CUB_ORACLE)
+        .id();
+    let cobra_id = scenario.add_creature(P0, "Lotus Cobra", 2, 1).id();
+    let first_land_id = scenario.add_land_to_hand(P0, "First Land").id();
+    let second_land_id = scenario.add_land_to_hand(P0, "Second Land").id();
+
+    let mut runner = scenario.build();
+    runner.state_mut().max_lands_per_turn = 2;
+    runner
+        .state_mut()
+        .objects
+        .get_mut(&cobra_id)
+        .expect("Lotus Cobra should start on the battlefield")
+        .counters
+        .insert(CounterType::Plus1Plus1, 1);
+
+    resolve_cub_landfall(&mut runner, first_land_id, cobra_id);
+    assert_eq!(
+        runner.state().objects[&cobra_id]
+            .counters
+            .get(&CounterType::Plus1Plus1)
+            .copied(),
+        Some(2),
+        "the first landfall resolution should place one +1/+1 counter on the seeded target"
+    );
+
+    resolve_cub_landfall(&mut runner, second_land_id, cobra_id);
+    assert_eq!(
+        runner.state().objects[&cobra_id]
+            .counters
+            .get(&CounterType::Plus1Plus1)
+            .copied(),
+        Some(4),
+        "the second landfall resolution should double Lotus Cobra's counters"
+    );
+    assert_eq!(
+        runner
+            .state()
+            .ability_resolutions_this_turn
+            .get(&(cub_id, 0)),
+        Some(&2),
+        "both landfall triggers should share Cub's printed ability index"
+    );
+}