diff --git a/src/bun.js/bindings/ZigGlobalObject.cpp b/src/bun.js/bindings/ZigGlobalObject.cpp
index 159a8459c9d28b..f8ff88e05fa7aa 100644
--- a/src/bun.js/bindings/ZigGlobalObject.cpp
+++ b/src/bun.js/bindings/ZigGlobalObject.cpp
@@ -285,11 +285,16 @@ static JSValue formatStackTraceToJSValue(JSC::VM& vm, Zig::GlobalObject* globalO
     size_t framesCount = callSites->length();
 
     WTF::StringBuilder sb;
+
     if (JSC::JSValue errorMessage = errorObject->getIfPropertyExists(lexicalGlobalObject, vm.propertyNames->message)) {
+        RETURN_IF_EXCEPTION(scope, {});
         auto* str = errorMessage.toString(lexicalGlobalObject);
+        RETURN_IF_EXCEPTION(scope, {});
         if (str->length() > 0) {
+            auto value = str->value(lexicalGlobalObject);
+            RETURN_IF_EXCEPTION(scope, {});
             sb.append("Error: "_s);
-            sb.append(str->value(lexicalGlobalObject).data);
+            sb.append(value.data);
         } else {
             sb.append("Error"_s);
         }
@@ -297,18 +302,23 @@ static JSValue formatStackTraceToJSValue(JSC::VM& vm, Zig::GlobalObject* globalO
         sb.append("Error"_s);
     }
 
-    if (framesCount > 0) {
-        sb.append("\n"_s);
-    }
-
     for (size_t i = 0; i < framesCount; i++) {
+        sb.append("\n    at "_s);
+
         JSC::JSValue callSiteValue = callSites->getIndex(lexicalGlobalObject, i);
-        CallSite* callSite = JSC::jsDynamicCast<CallSite*>(callSiteValue);
-        sb.append("    at "_s);
-        callSite->formatAsString(vm, lexicalGlobalObject, sb);
         RETURN_IF_EXCEPTION(scope, {});
-        if (i != framesCount - 1) {
-            sb.append("\n"_s);
+
+        if (CallSite* callSite = JSC::jsDynamicCast<CallSite*>(callSiteValue)) {
+            callSite->formatAsString(vm, lexicalGlobalObject, sb);
+            RETURN_IF_EXCEPTION(scope, {});
+        } else {
+            // This matches Node.js / V8's behavior
+            // It can become "at [object Object]" if the object is not a CallSite
+            auto* str = callSiteValue.toString(lexicalGlobalObject);
+            RETURN_IF_EXCEPTION(scope, {});
+            auto value = str->value(lexicalGlobalObject);
+            RETURN_IF_EXCEPTION(scope, {});
+            sb.append(value.data);
         }
     }
 
@@ -684,8 +694,8 @@ static JSValue computeErrorInfoWithPrepareStackTrace(JSC::VM& vm, Zig::GlobalObj
 
         for (size_t i = 0; i < framesCount; i++) {
             JSC::JSValue callSiteValue = callSites.at(i);
-            CallSite* callSite = JSC::jsDynamicCast<CallSite*>(callSiteValue);
             if (remappedFrames[i].remapped) {
+                CallSite* callSite = JSC::jsCast<CallSite*>(callSiteValue);
                 callSite->setColumnNumber(remappedFrames[i].position.column());
                 callSite->setLineNumber(remappedFrames[i].position.line());
             }
diff --git a/test/js/node/v8/capture-stack-trace.test.js b/test/js/node/v8/capture-stack-trace.test.js
index 9feaa8d12a040a..69dcf9307fa928 100644
--- a/test/js/node/v8/capture-stack-trace.test.js
+++ b/test/js/node/v8/capture-stack-trace.test.js
@@ -663,3 +663,37 @@ test("calling .stack on a non-materialized Error updates the stack properly", fu
   expect(stack).toContain("hey");
   expect(stack).toContain("wrapped");
 });
+
+test("Error.prepareStackTrace on an array with non-CallSite objects doesn't crash", () => {
+  const result = Error.prepareStackTrace(new Error("ok"), [{ a: 1 }, { b: 2 }, { c: 3 }]);
+  expect(result).toBe("Error: ok\n    at [object Object]\n    at [object Object]\n    at [object Object]");
+});
+
+test("Error.prepareStackTrace calls toString()", () => {
+  const result = Error.prepareStackTrace(new Error("ok"), [
+    { a: 1 },
+    { b: 2 },
+    {
+      c: 3,
+      toString() {
+        return "potato";
+      },
+    },
+  ]);
+  expect(result).toBe("Error: ok\n    at [object Object]\n    at [object Object]\n    at potato");
+});
+
+test("Error.prepareStackTrace propagates exceptions", () => {
+  expect(() =>
+    Error.prepareStackTrace(new Error("ok"), [
+      { a: 1 },
+      { b: 2 },
+      {
+        c: 3,
+        toString() {
+          throw new Error("hi");
+        },
+      },
+    ]),
+  ).toThrow("hi");
+});