diff --git a/xenomorph/xenomorph/helper.rkt b/xenomorph/xenomorph/helper.rkt
index 13705e87..3e7c9dd1 100644
--- a/xenomorph/xenomorph/helper.rkt
+++ b/xenomorph/xenomorph/helper.rkt
@@ -4,7 +4,7 @@
          "generic.rkt")
 (provide (all-defined-out))
 
-(struct x:ptr (type val parent) #:transparent #:mutable)
+(struct x:ptr (type val parent) #:transparent)
 
 (define x:version-key 'x:version)
 (define x:start-offset-key 'x:start-offset)