Acorn barnacle

The acorn barnacle is a type of sea creature in the introduced in.

While initially absent from, the Acorn Barnacle was added in the 1.3.0 Free Summer Update.

In
Upon donating an acorn barnacle to the museum, it can be found in the large pool in the first room of the Sea exhibit, along with many other species of sea creatures. It is found on the large rock. The exhibit has this to say about the acorn barnacle:

In
When donating to the museum, Blathers will say the following:

In
During a Fishing Tourney, when given an acorn barnacle, Chip will not score the sea creature but will say the following:

Real-world info
The acorn barnacle, Balanus glandula, can be found from Alaska, USA to Bahia San Quentin, Baja California. They are moderate-sized with a diameter to 22mm (0.9m). The shell is formed by plates on top of each other, and they can get oxygen from air and water. They can also live up to 10 years.