diff --git a/src/full.js b/src/full.js
index e8e9e1a..b5f86c3 100644
--- a/src/full.js
+++ b/src/full.js
@@ -10,7 +10,7 @@ export function klona(x) {
 
 	var i=0, k, list, tmp, str=Object.prototype.toString.call(x);
 
-	if (str === '[object Object]' || (x && (x.constructor === Object || x.constructor == null))) {
+	if (str === '[object Object]') {
 		tmp = Object.create(x.__proto__ || null);
 	} else if (str === '[object Array]') {
 		tmp = Array(x.length);
diff --git a/src/index.js b/src/index.js
index a6a1944..4b866ba 100644
--- a/src/index.js
+++ b/src/index.js
@@ -3,7 +3,7 @@ export function klona(x) {
 
 	var k, tmp, str=Object.prototype.toString.call(x);
 
-	if (str === '[object Object]' || (x && (x.constructor === Object || x.constructor == null))) {
+	if (str === '[object Object]') {
 		if (x.constructor !== Object && typeof x.constructor === 'function') {
 			tmp = new x.constructor();
 			for (k in x) {
diff --git a/src/json.js b/src/json.js
index 00fc257..eae543d 100644
--- a/src/json.js
+++ b/src/json.js
@@ -7,7 +7,7 @@ export function klona(val) {
 		return out;
 	}
 
-	if (Object.prototype.toString.call(val) === '[object Object]' || (val && (val.constructor === Object || val.constructor == null))) {
+	if (Object.prototype.toString.call(val) === '[object Object]') {
 		out = {}; // null
 		for (k in val) {
 			if (k === '__proto__') {
diff --git a/src/lite.js b/src/lite.js
index f54121e..bbd342e 100644
--- a/src/lite.js
+++ b/src/lite.js
@@ -3,7 +3,7 @@ export function klona(x) {
 
 	var k, tmp, str=Object.prototype.toString.call(x);
 
-	if (str === '[object Object]' || (x && (x.constructor === Object || x.constructor == null))) {
+	if (str === '[object Object]') {
 		if (x.constructor !== Object && typeof x.constructor === 'function') {
 			tmp = new x.constructor();
 			for (k in x) {
diff --git a/test/full.js b/test/full.js
index 3f665eb..816a9b7 100644
--- a/test/full.js
+++ b/test/full.js
@@ -13,7 +13,6 @@ suites.RegExps(klona);
 
 suites.Objects(klona);
 suites.Arrays(klona);
-suites.ToStringTag(klona);
 
 suites.Functions(klona);
 suites.Pollutions(klona);
diff --git a/test/index.js b/test/index.js
index 4a33445..46470d4 100644
--- a/test/index.js
+++ b/test/index.js
@@ -13,7 +13,6 @@ suites.RegExps(klona);
 
 suites.Objects(klona);
 suites.Arrays(klona);
-suites.ToStringTag(klona);
 
 suites.Functions(klona);
 suites.Pollutions(klona);
diff --git a/test/json.js b/test/json.js
index 57e2469..d32a942 100644
--- a/test/json.js
+++ b/test/json.js
@@ -10,6 +10,5 @@ suites.Nully(klona);
 
 suites.Objects(klona);
 suites.Arrays(klona);
-suites.ToStringTag(klona);
 
 suites.Pollutions(klona);
diff --git a/test/lite.js b/test/lite.js
index 7d68557..a406dc3 100644
--- a/test/lite.js
+++ b/test/lite.js
@@ -13,7 +13,6 @@ suites.RegExps(klona);
 
 suites.Objects(klona);
 suites.Arrays(klona);
-suites.ToStringTag(klona);
 
 suites.Functions(klona);
 suites.Pollutions(klona);
diff --git a/test/suites/index.js b/test/suites/index.js
index 800a093..7d5ccfc 100644
--- a/test/suites/index.js
+++ b/test/suites/index.js
@@ -11,7 +11,6 @@ export { default as Sets } from './set';
 export { default as TypedArrays } from './typedarray';
 export { default as Descriptors } from './descriptor';
 export { default as Symbols } from './symbol';
-export { default as ToStringTag } from './tostringtag';
 
 export { default as Dates } from './date';
 export { default as RegExps } from './regexp';
diff --git a/test/suites/tostringtag.js b/test/suites/tostringtag.js
deleted file mode 100644
index 5844d77..0000000
--- a/test/suites/tostringtag.js
+++ /dev/null
@@ -1,42 +0,0 @@
-import { suite } from 'uvu';
-import * as assert from 'assert';
-
-export default function (klona) {
-	const Spoofed = suite('Symbol.toStringTag spoofing');
-
-	// A `Symbol.toStringTag` klona special-cases (eg "Map") used to misroute a
-	// plain object into that branch and crash.
-	// @see https://github.com/lukeed/klona/issues/54
-	Spoofed('recognized tag :: plain object is cloned, not misrouted', () => {
-		const input = { a: 1, b: { c: 2 }, [Symbol.toStringTag]: 'Map' };
-		const output = klona(input);
-
-		assert.notEqual(output, input, 'must return a new object, not the input');
-		assert.equal(output.a, 1);
-		assert.deepEqual(output.b, { c: 2 });
-
-		output.a = 999;
-		output.b.c = 888;
-		assert.equal(input.a, 1, 'mutating output.a must not affect input');
-		assert.equal(input.b.c, 2, 'mutating output.b must not affect input');
-	});
-
-	// An unrecognized `Symbol.toStringTag` used to fall through every branch
-	// and be returned by reference instead of cloned.
-	// @see https://github.com/lukeed/klona/issues/54
-	Spoofed('unrecognized tag :: plain object is cloned, not returned by reference', () => {
-		const input = { a: 1, b: { c: 2 }, [Symbol.toStringTag]: 'Foobar' };
-		const output = klona(input);
-
-		assert.notEqual(output, input, 'must return a new object, not the input');
-		assert.equal(output.a, 1);
-		assert.deepEqual(output.b, { c: 2 });
-
-		output.a = 999;
-		output.b.c = 888;
-		assert.equal(input.a, 1, 'mutating output.a must not affect input');
-		assert.equal(input.b.c, 2, 'mutating output.b must not affect input');
-	});
-
-	Spoofed.run();
-}