Assuming this alien is from outer space, there's plenty of radiation out among the stars.
If we had something that could track radiation, we could get an idea of where the alien has been and discover anything it has left behind.
Fallout fans will already know - a geiger counter makes a ticking noise when near anything radioactive.
Geiger counters are cool, but only if you're a nerd - you'll probably find it in one of the boys' bedrooms.
Tony has glasses, and we're running on stereotypes.
Visit Tony's bedroom via the vines on his house, then take the geiger counter from the foreground near the books.
When you enter an area that's been visited by the alien, Vincent will mention the geiger counter starting to beep.
By using the geiger counter on anything it beeps near, you may be able to find the source of the radiation.
On Nick's street, you'll find something unusual by using the geiger counter on the bushes.
It seems to be the alien's missing eye - it'll definitely want that back!
Assuming the lure was the last thing you needed, that's now everything - use the lure on the hole in the woods and enjoy the show!