UB-Sludge
tar + glob
poison/rock
evolves into Creatore at level 35
Dex Entry: It may look cute, but Targlob is capable of melting geodes with its tar-like body. It's appetite is insatiable until it grows.

UB-Consume
creature + ore
Dex Entry: As Creatore gains limbs, it has more advantage scavenging gems and geodes. It'll avoid Carbink as they resent their jewels.
evolves into Morteluster at night while holding a Nebula Stone

UB-Cluster
mortem + cluster
Dex Entry: Now a colossal slime Pokémon, it's hunger for gems is satiated. But it'll still need to eat geodes to keep itself active. Its claws are capable of cutting steel like butter.

based on the tar monster from scooby doo and cluster crystals