The Hounds of Tindalos

Does anyone here have a favorite stories about these critters? I have just been reading a little about them. They sound familiar, but I can't remember where I might have read about them. It is possible I just read a sory that quickly mentioned them.... anyway, the idea of them is kind of interesting. They are mysterious, incomprehensible creatures from beyond time and space, and they are "attracted by time travel." When someone travels through time, they are alerted somehow, and they will track the time traveller down and fuck him up, bigtime.
https://en.wikipedia.org/wiki/Hounds_of_Tindalos


They were conceived by this guy, Frank Belknap Long. He sound spretty interesting too. Hmm, this says the Hounds of Tindalos are in a Metallica song, and in some novel by Brian Lumley. OK, I should be able to figure out where I have heard of them from this... here, in case anyone is interested, check this out:
https://en.wikipedia.org/wiki/Frank_Belknap_Long#Influence_on_popular_culture