Being especially grotesque, these moon mutated Pengulls will drain sanity when near and attack other mobs similarly to Hounds. This excludes other Pengulls or Moonrock Pengulls.
Just like normal Pengulls, they have a hunger bar that lasts for 12 days. They will take damage from starvation and will eventually die. The Moonrock Pengull drops Ice and Monster Meat upon being killed.