Resolved memory leak issue. Added cleanup script to event cleanup. When the player would change rooms the ds_lists would be left in memory. To resolve this I added a simple clean up to delete the ds_lists on the clean up event.
Added a new project that uses arrays.
This asset's design was intended to be one usable script without any outside help. For example you would NOT need to init any variables in the create event. However after fixing the memory leak this was impossible with ds_lists. By having to add a script to the given object's clean up event this means it is not a single script. I reworked the asset to use arrays. GMS automatically cleans up arrays on its own when the game ends or when the room changes or even if the instance itself is destroyed. Now you can download both the array version or the ds_list version. The choice of which one you want to use is yours.
Enjoy the update and good luck on all your Game Development Endeavors.