Crash in-battle

Windows 10, Siralim v0.5.9. Last thing that happened was a crypt bat attacking


############################################################################################
FATAL ERROR in
action number 1
of Step Event0
for object obj_battlecontroller:

trying to index a variable which is not an array
at gml_Script_bc_OnDeath
############################################################################################

stack frame is
gml_Script_bc_OnDeath (line -1)
gml_Script_bc_ExecuteEvents
gml_Object_obj_battlecontroller_Step_0

My creatures artefact traits, from left to right: Simulacrum, Wreck, Final Breath, Swiftcasting, Pandemonium Rebirth, Whirlstorm.