Prop Easter Egg, how to?

I wanted to know how to make some kind of “puzzle easter egg”. A prop_physics that when hits a trigger reveals the easter egg. But I want a certain prop_physics not any prop_physics. How to do this?

Have a trigger_once, a prop_physics and a filter_activator_name.

Give the filter_activator_name a name and a filter name. (Filter name = the name of the prop_physics)
Give the prop_physics the same name you put as the filter name.
Then select the trigger_once, and set the Filter name keyvalue to the name of the filter_activator_name.

Now, only props with the name specified in the filter_activator_name can trigger it. Remember to have “physics objects” checked in the flags of the trigger_once.

If that explanation sounds messy (which it is), just use these keyvalues:

filter_activator_name

Name: propfilter
Filter Name: activatorprop

prop_physics

Name: activatorprop

trigger_once

Filter Name: propfilter

The placement of the trigger_activator_name does not matter.

Thanks