Clotty

Clotties are enemies that wander around the room, randomly shooting four blood shots in the cardinal directions. These can be particularly difficult to deal with early on if the player isn't careful. Two of them are also spawned from Mega Clotties when killed. They are immune to any fire damage and will turn into Grilled Clotties when set on fire.

Clot
A Clot is an alternate version of a Clotty that shoots four tar shots in the diagonal directions. They appear similar to Gish, who also spawns them. As they do not shoot tar shots in the cardinal directions, they are considerably easier to defeat than Clotties.

I.Blob
The I.Blob is an even rarer alternate version of the Clotty. It is an Isaac-like blob that shoots 8 blood shots in all directions, combining the attacks of both the Clotty and the Clot.

Grilled Clotty
The Grilled Clotty is an enemy that behaves exactly like a Clotty; however, it moves much quicker. Clotties transform into Grilled Clotties when set on fire.

Cloggy
The Cloggy is an enemy that behaves similarly to a Clotty; however, its shots are brown and curved rather than straight. Its bullets alternate clockwise and counterclockwise with each shot.

Trivia

 * Clots are a miniature version of Gish, from the game of the same name.
 * The I in I.Blob probably stands for Isaac due to their appearance.