Some developers really love to play with UV Lights, and that's exactly what Grand Theft Auto V Developer Rockstar did with the map included in the collector's edition of the game, as discovered by NeoGaf user EatChildren.

When exposed to an UV Light, the map shows a secret message apparently left by Trevor and a few other tidbits.

T.P.E - Trevor Philips Enterprises.

Weaponry, narcotics, intimidation and casual wear.

Lago Zan Cudo.

Great Ocean, Highway north,

through north Chumash,

0.5 miles past Raton Canyon.

When guard rail ends,

follow the dirt road down the docks.

Bring $500,000 cash.

You can check out the pictures of the discovered details in the gallery below, and head to find out what the message hides. Time for some treasure hunting!