Underleveled Pokémon
From TPPC Wiki
An underleveled (UL) Pokémon is an evolved Pokémon that exists at a level lower than it's normal evolution level.
For example, GoldenHoundour evolves into GoldenHoundoom at Level 750. As a result, a GoldenHoundoom Level 100 may be referred to as underleveled.
Pokémon may be underleveled for a variety of reasons. They may be Promos, past errors, created by staff and/or arise due to the re-scaling of stats and evolution levels that occurred in later versions of TPPC.