How do I set variables in a newly created object

In something like gamemaker I can do this 'x=instance_create(the thing,x,y);

then I can adjust variables in it with code like x.snazzy = 5

How can I adjust variables in only the object most recently created?

Any actions under the same event will refer to the same object that was already picked. eg

The second action affects only the object created in the first action.

You can also use On-created event to do actions on the object being created.

On created sprite1 set var x.snazzy = 5