diff --git a/src/untrusted/lib/createContext.ts b/src/untrusted/lib/createContext.ts
index 6fb2313..5919869 100644
--- a/src/untrusted/lib/createContext.ts
+++ b/src/untrusted/lib/createContext.ts
@@ -126,9 +126,6 @@ const setupContextGlobalRefs = (ctx: object) => {
  */
 const createGlobalFunctionProxy = (() => {
 	return (ctx: object, fn: typeof Function.prototype) => {
-		// Do not proxy constructors
-		if (fn.prototype && fn.prototype.constructor === fn) return fn;
-
 		return new PX(fn, {
 			['apply'](o, thisArg, argArray) {
 				if (typeof o === 'function') {
@@ -141,6 +138,9 @@ const createGlobalFunctionProxy = (() => {
 
 				throw TE('Not a function');
 			},
+			['setPrototypeOf']() {
+				return false;
+			},
 		});
 	};
 })();