Wizkids Rules!

Blob UC:

When fielded, capture target opposing character die until Blob leaves the Field Zone.

Blob Common:

When fielded, capture all opposing Sidekick dice until Blob leaves the Field Zone or you field another Blob die.

What happens if you blank Blobs text? Do the dice that are captured get released? Or do they sit in limbo?

stevomuck wrote:Blob UC:

When fielded, capture target opposing character die until Blob leaves the Field Zone.

Blob Common:

When fielded, capture all opposing Sidekick dice until Blob leaves the Field Zone or you field another Blob die.

What happens if you blank Blobs text? Do the dice that are captured get released? Or do they sit in limbo?

When the text of a die that currently has other dice captured loses its text or has its text ignored (“blanked” in your terms), all of the captured dice are returned to the location they were when they were captured. When the capturing die regains its text, nothing happens: it does not re-capture the dice that were originally captured.

To directly answer your question: if either of those two versions of Blob have their text ignored while they have a die captured, the captured die would be returned to the Field Zone.