Arena crash

Reaching the point where the opponent’s sprite would enter the battlefield in tthe Arena throws up a code error, crashing the game. I am very upset. I had a wonderfully tanky team set up.

Version: 0.6.1
OS: Windows 10
Log:


############################################################################################
ERROR in
action number 1
of Draw Event
for object obj_arena:

REAL argument is undefined############################################################################################
gml_Object_obj_arena_Draw_0 (line 15)