diff --git a/code/__DEFINES/spaceman_dmm.dm b/code/__DEFINES/spaceman_dmm.dm
index c74ad576085..c2ecc6a5e66 100644
--- a/code/__DEFINES/spaceman_dmm.dm
+++ b/code/__DEFINES/spaceman_dmm.dm
@@ -31,6 +31,9 @@
 /proc/auxtools_stack_trace(msg)
 	CRASH(msg)
 
+/proc/auxtools_expr_stub()
+	CRASH("auxtools not loaded")
+
 /proc/enable_debugging(mode, port)
 	CRASH("auxtools not loaded")