Slimey is a gigantic octopus like creature who lives in the lake, and the most frequent appearing reoccurring character in the series. While he terrified the campers on their first appearance by grabbing them and tossing them in the air, it's revealed he actually wants to play with them. He later becomes quite good friends with the campers, especially Squirt, and will often provide them with fun by tossing them into the air when they're swimming so that they can dive. He obeys any of the counselors and will quite often aid the campers during their adventures involving the lake. Only his tentacles are shown, so it is unknown what his body looks like.
Slimey is a large Octopus or Squid that lives in Lake Icky Gloomy. All the viewers sees is its tentacles. They are very powerful because it is able to destroy the bridge leading to Camp Lakebottom. Slimey is very careful that it can hold up the campers and jump of them. The other thing about Slimey is that it does not speak but can create images on its tentacles.
If Voyage to the Bottom of the Deep is like the real Camp Lakebottom, Slimey would be a squid as the tentacle creature in Camp Bottomlake is called a squid and presents as one with two specialized tentacles.
However, this creature could just refer to Buttsquat as they do name it Squidsquat.