diff --git a/scripts/fuzz_shell.js b/scripts/fuzz_shell.js
index 718692498d1..de1ef135202 100644
--- a/scripts/fuzz_shell.js
+++ b/scripts/fuzz_shell.js
@@ -270,8 +270,10 @@ var imports = {
     // Throw an exception from JS.
     'throw': (which) => {
       if (!which) {
-        throw 'some JS error';
+        // Throw a JS exception.
+        throw 0;
       } else {
+        // Throw a wasm exception.
         throw new WebAssembly.Exception(wasmTag, [which]);
       }
     },
diff --git a/src/tools/execution-results.h b/src/tools/execution-results.h
index c6cb7ecc571..9ef409a385d 100644
--- a/src/tools/execution-results.h
+++ b/src/tools/execution-results.h
@@ -182,7 +182,8 @@ struct LoggingExternalInterface : public ShellExternalInterface {
 
   void throwJSException() {
     // JS exceptions contain an externref, which wasm can't read (so the actual
-    // value here does not matter).
+    // value here does not matter, but it does need to match what the 'throw'
+    // import does in fuzz_shell.js, as the fuzzer will do comparisons).
     Literal externref = Literal::makeI31(0, Unshared).externalize();
     Literals arguments = {externref};
     auto payload = std::make_shared<ExnData>(jsTag, arguments);
diff --git a/test/lit/d8/fuzz_shell_exceptions.wast b/test/lit/d8/fuzz_shell_exceptions.wast
index 6b46ee2adfa..da1e7fbe0aa 100644
--- a/test/lit/d8/fuzz_shell_exceptions.wast
+++ b/test/lit/d8/fuzz_shell_exceptions.wast
@@ -31,7 +31,7 @@
 ;; RUN: v8 %S/../../../scripts/fuzz_shell.js -- %t.wasm | filecheck %s
 ;;
 ;; CHECK: [fuzz-exec] calling throwing-js
-;; CHECK: exception thrown: some JS error
+;; CHECK: exception thrown: 0
 ;; CHECK: [fuzz-exec] calling throwing-tag
 ;; CHECK: exception thrown: [object WebAssembly.Exception]