Wells are circular holes which may contain a cave to explore or a Worm in a Well, which will try to hurt Croc if he gets too close. Some wells with a cork require Croc to stomp on the top to get into it. Most Wells with Worms in have Jellies within them to stop him going further into the Well, apart from the first one in And So The Adventure Begins. A Worm in a Well can hide in a green Well and on one occasion a bricked Well (And So The Adventure Begins). They only appear on Forest Island, however, Worms in Wells also appear on Ice Island. There is also a Heart in one worm in a Well located in The Curvy Caverns.
In Underground Overground, there are two Wells at the beginning of the level. The bottom one will lead to the rest of the level, but will miss a cave only reachable using the top Well.