I. Blob (fully known as Isaac Blob) is a type of Clotty added in the Wrath of the Lamb DLC for the original game, and also appear in the Rebirth remake. Aside from their Monstro-like appearance, they actually bear resemblances to Isaac in the form of a blob.
BehaviorI. Blob is a rare enemy to encounter as it sometimes replaces Clot or Clotty which aren't common enemies either. They can be found in any place where Clotties and Clots would appear.
I. Blob fires in 8-directions, combining the cross pattern shots from Clotty and diagonal pattern from Clot, making it extremely dangerous. As with Clotty, it is recommended to employ bombs or activated items against it, and having spectral or homing tears will do a lot to shift the odds in your favor.