I've previously gone through the animals in Elden Ring Runes, explaining how the wolves, bears, as well as birds pose an even bigger threat than its otherworldly bosses. However, a pack of bloody dogs put everything else to shame.
A vicious breed of undead dog referred to as the Rotten Stray can be found across all over the Lands Between, often in vicious packs. While they're easy to dispatch in the majority of cases as in the absence of getting overly greedy, a sour version that is found at the Altus Plateau's Writheblood Ruins amplifies their biting attacks with a bleed effect that can catch you off guard if you're not careful.
Bleed, as with all health effects, develops slowly after repeated blows, and drains a massive amount of your health when it has reached its limit. It's a pain to combat, however it's not something that's going to happen in the instant or catch you off guard. Therefore, the Writheblood Ruins dogs' overwhelming ability to inflict bleed instantaneously is an alarming anomaly.
As seen in the video above, these strays appear to be infected. The normal attacks they use work as intended, but the combos hit way many times, as evidenced by the multiple sound effects and rapid bleeding. Even a person with the highest level of endurance and vitality stats that govern in addition to health points and bleed resistance as well as heavy-duty armor will not last longer than a couple of seconds before bleeding into the next.
Based on user comments on Fextralife, a wiki for info on Elden Ring as well as other Souls games, Writheblood Ruins was at time also the home of the immortal slime, however I haven't been able to locate footage of the adversary in combat. It was apparently fixed with the latest 1.03 patch.
Although Elden Ring Runes buy has its fair number of bugs, it just comes with the territory. Development can be difficult even in the best of times. Considering the problems of the last few years, it's not a wonder that FromSoftware could launch something that ambitious and remains functional for most people. (It's definitely not Cyberpunk 2077). Just sit tight and maybe steer clear of this part of the game for now.