Lump

The Lump is a Monster that can be encountered in Chapter 4. It appears as a red lump popping out of the ground, with a gaping mouth and two beady eyes. It attacks by shooting a spread of three shots at Isaac when he comes within range, then burrowing underground and resurfacing in a different part of the room. Lumps will also burrow underground if the player doesn't come in its range for a certain amount of time.

Trivia

 * Lumps had a radically different appearance in the original Binding of Isaac.
 * Lumps are similar in appearance to the Betus enemies from one of Edmund McMillen's previous games, Super Meat Boy.
 * Previously, Lumps appeared as Light Brown in the . As of Booster Pack #5, Lumps are now red in this environment.

Tar Boy
Tar Boys were added in Booster Pack #4.

The Tar Boy occasionally fires a short-ranged spray of shots towards Isaac that leaves behind slowing Black Creep. It can also burrow underground and resurface in a different part of the room, much like the Lump. However, it is only able to resurface in areas that have black creep. Tar Boys prefer to resurface close to Isaac, and can even resurface directly under him if he's standing on black creep.

If Isaac is standing on Black Creep, Tar Boys can cause a fountain of shots to fire straight upwards out of the Creep where Isaac is standing/ create a Nerve Ending-like tentacle directly underneath Isaac. This can also occur with Black Creep spawned by other enemies such as Gushes. The tentacle can also hit the player even if they posses flight.