Treasure Imp is an imp enemy. At the lowest Threat it has 130 health, hits for 0 and carries 0 armor. It moves at 4.5, can reach you from 1 away, and telegraphs each swing for 10 ticks before it lands, then waits 30 before the next one.

It is part of the shared Demon Gate crowd rather than any one biome, so it can show up almost anywhere.

Killing it pays 40 XP, and it drops something 100% of the time, and it runs when it is losing.