There is a creature briefly mentioned in an anecdote in the the book "Visions and Beliefs in the West of Ireland" by Lady Augusta Gregory that has captured my imagination something fierce.

It's in the chapter "Monsters and Sheoguey Beasts". An individual interviewed mentions an encounter with a creature they describe as having "the head (of a) pike". The thing had come into their room in the dead of night and got into what sounds like a rather intense fight with the individual's dog (lots of jumping around by both combatants is mentioned) before being seemingly chased off. Though it seems the dog didn't like going into the room after that.

I don't know if it's the creepiness of the incident, or my general love of aquatic monsters, but this piscine monster has been living rent free in my head ever since I read about it. My questions are nearly endless.

Are there other stories of a similar creature in any folklore or myth elsewhere in Ireland? Does this thing have a name, and if not, what might one call it?

I swear, a part of me wants to write a story about this thing or make a whole fictional ecology on it like some kind of naturalist. I'm hooked.

Here's a link to the passage in question, under "I have been told by a car-driver":

https://sacred-texts.com/neu/celt/vbwi/vbwi17.htm

Creature described in Visions and Beliefs in the West of Ireland