the watcher in the water

[Iargwath]

'What was the thing, or were there many of them?', [Gandalf's only answer is] 'I do not know.'

The Fellowship of the Ring II ch 4 Journey in the Dark
The Watcher in the Water is one of the most unique creatures in the books. It is discussed nowhere else. Its general description is that of a many tentacled squid like creature, but Tolkien never states this. So it is not definant that it is a 'Kraken' (large squid). It could be entirely something else.