multiplicative blood - makes the majority of blood visuals use multiplicative blending

code/datums/mutable_appearance.dm

@@ -10,7 +10,7 @@
 						// And yes this does have to be in the constructor, BYOND ignores it if you set it as a normal var
 
 // Helper similar to image()
-/proc/mutable_appearance(icon, icon_state = "", layer = FLOAT_LAYER, plane = FLOAT_PLANE, alpha = 255, appearance_flags = NONE, color = "#FFFFFF")
+/proc/mutable_appearance(icon, icon_state = "", layer = FLOAT_LAYER, plane = FLOAT_PLANE, alpha = 255, appearance_flags = NONE, color = "#FFFFFF", blend_mode = BLEND_DEFAULT)
 	var/mutable_appearance/MA = new()
 	MA.icon = icon
 	MA.icon_state = icon_state
@@ -19,5 +19,6 @@
 	MA.alpha = alpha
 	MA.appearance_flags |= appearance_flags
 	MA.color = color
+	MA.blend_mode = blend_mode
 	return MA