TERA players are invited to head into the game to take part in a new event called TERA Mongo. The idea is for players to hunt down and kill Mongos, monsters that can appear in strange places. Finding and killing these creatures can yield enchanting materials and cosmetic items. Uncommon and rare Mongos can also drop a mount.
If that doesn't have your Pokemon Go senses tingling, it's worth noting that "evolved" versions of Mongos can also appear that can drop more and better rewards.
Head to the TERA site to get hold of a TERA Mongo card to keep track of the Mongos slain (or down below). As the site says, "No need for a mobile device or to go outside at all"!