Rocksters spawn on beaches near rivers, large lakes, or the ocean. They spawn in multiple sizes ranging from less than half the player to more than 2x the player's size.
The biggest Rockster is of course their boss: Rockzilla
Rocksters can tuck in their claws and turn invulnerable and immobile for ~4 seconds, after which they'll perform a spinning attack that can send a player flying.
Before April 2017, to kill a Rockster, you had to strike them (only while they weren't blocking!) 22 times with a Twig, 15 times with a Wood Sword, 10 times with a Stone Sword, 4 times with an Obsidian Sword, or 2 times with an Iron Sword, Diamond Sword, or Lumite Sword. With update R41 the hitpoints of Rocksters have been reduced.
Rocksters, when killed or dismissed, drop a few different items, just alike their brethren, the Night Rocksters:
- 1-3 Rockster Rocks
- 1-2 (blocks of) Coral
- 1-2 (blocks of) Magnetite (only rarely)
- 1-2 (blocks of) Mud
and can also additionally drop (like many other creatures):
You can harvest the same materials from them as Pets as would be in their loot-bag, just in larger amounts.