Claim Clams
Claim Clams are a feature introduced in Changelog 13 along with a variety of other ocean themed functionalities. Clams serve to moderate the world claiming process by making sure that users do not claim too many(or too little) worlds.

Functionality
How to obtain
Users obtain Claim Clams by visiting a reefworld, which spawns from a regular world after it has been inactive for long enough.
Hyperclaiming
If a user claims too many worlds within a short amount of time, then the Claim Clam will randomly devour 25% of their owned worlds.
This measure was implemented by FP to counteract hyperclaiming, where users would clog up the server by creating egregious quantities of empty or low quality worlds.
Autoclaiming
On the other hand, claiming too little worlds(hypoclaiming) will cause the Claim Clam to autoclaim a large number of worlds.
This measure was implemented to counteract a drought of content by pressuring users to create more worlds.
Claim clam duplication
In cases where a user creates a truly outlandish amount of pages, the Claim Clam will spawn another version of itself and double all of the effects mentioned on this page.
How to remove claim clams
You can get rid of it though by feeding it a poisoned world, which are added in the same update
When you go over the rate limit. The poison level of the world goes up past a certain point, it becomes a poisoned world for 24h afterwards.
Claim Clam Cam
You can use the Claim Clam Cam to watch the clams without them seeing you.
Be careful using it though since if they notice it, they'll get angry.