diff --git a/lib/mammoth/CMakeLists.txt b/lib/mammoth/CMakeLists.txt
index 1c0f027..e177ddd 100644
--- a/lib/mammoth/CMakeLists.txt
+++ b/lib/mammoth/CMakeLists.txt
@@ -10,6 +10,7 @@ target_include_directories(mammoth_lib
   PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
 
 target_link_libraries(mammoth_lib
+  c
   zion_lib)
 
 set_target_properties(mammoth_lib PROPERTIES
diff --git a/lib/mammoth/include/mammoth/debug.h b/lib/mammoth/include/mammoth/debug.h
index 118d0fa..800a05a 100644
--- a/lib/mammoth/include/mammoth/debug.h
+++ b/lib/mammoth/include/mammoth/debug.h
@@ -3,7 +3,7 @@
 #include <stdint.h>
 #include <zerrors.h>
 
-void dbgln(const char*);
+void dbgln(const char* fmt, ...);
 
 // Checks that the code is ok.
 // if not exits the process.
diff --git a/lib/mammoth/src/debug.cpp b/lib/mammoth/src/debug.cpp
index 665e08c..cbe8632 100644
--- a/lib/mammoth/src/debug.cpp
+++ b/lib/mammoth/src/debug.cpp
@@ -1,13 +1,29 @@
 #include "include/mammoth/debug.h"
 
+#include <stdarg.h>
+#include <stdio.h>
 #include <zcall.h>
 #include <zerrors.h>
 
-void dbgln(const char* str) {
-  // Safe to ignore the result since right now this doesn't throw.
+void dbgln_internal(const char* str) {  // Safe to ignore the result since right
+                                        // now this doesn't throw.
   uint64_t _ = ZDebug(str);
 }
 
+void dbgln(const char* fmt, ...) {
+  char str[1024];
+  va_list arg;
+  va_start(arg, fmt);
+  int ret = vsprintf(str, fmt, arg);
+  va_end(arg);
+
+  if (ret == -1 || ret > 1024) {
+    crash("Bad vsprintf", 1);
+  }
+
+  dbgln_internal(str);
+}
+
 void check(uint64_t code) {
   switch (code) {
     case Z_OK: