I think this is a peanut worm. Lurking under a rock.
from benthic grab
Collected from one cubic foot of backreef substrate plus water in the lagoon behind Carrie Bow Cay. CBCUBE_03_BCBC_157_Hemichordata_09.jpg
Today I observed several parchment-like tube that I believe are of acorn worms (class Enteropneusta) at University Beach, Corpus Christi Bay, Texas.
I visit this beach on a weekly basis, but I don't remember ever seeing these tubes. Maybe the strong winds brought them in?
In the biotic inventory of the Gulf of Mexico, Chris Cameron listed 5 species of acorn worms from the Gulf of Mexico, but only one species, Schizocardium braziliense Spengel, 1893, was reported in Texas. It actually was a new record for the Gulf, from Laguna Madre, Corpus Christi, where it was found to be abundant in 6 m of water. See more at BioGoMx:
This is an acorn it is dark brown on the bottom and light brown on the top. It was in the grass at umass next to a tree and amongst other acorns. The acorn is extremely hard except the top of the acorn is still hard but softer than the bottom.
Los hemicordados (Hemichordata) o faringotremados (Faringotremata) son un filo de animales deuteróstomos, de aspecto vermiforme, que se suele relacionar con los cordados, pero no presentan una auténtica notocorda, sino una estomocorda que es una expansión del tubo digestivo; como los cordados, presentan una faringe con hendiduras (faringotremas), que usan para filtrar del alimento.