I employed all the debug messages you recommended and fixed all bugs accordingly. Everything seemed to make sense except for one thing. I got this warning during decompiling.

ERROR in action number 1 of Create Event for object o_hitbox:

Variable o_hitbox.creator(100057, -2147483648) not set before reading it. at gml_Object_o_hitbox_Create_0 (line 1) - show_debug_message("Hitbox(" + string(id) + ") created by: " + string(creator.id) );

gml_Object_o_hitbox_Create_0 (line 1) gml_Script_create_hitbox (line 19) gml_Object_ObjectEnemy_Step_0 (line 133) - create_hitbox(x+(image_xscale * 4), y, self, enemy_attack_one_damage, 4, 4, 5, image_xscale); //"+(image_xscale * 10)" add this to x to make the attack go farther

This suggests that something is wrong with the creator variable.