My Dog is INDESTRUCTIBLE?!

So today, I was playing Minecraft, minding my own business on my plot on my usual creative server. I had my dog, Otaku, outside while I was putting carpet on the upstairs of my house when a troll appeared (wearing a troll face head). So I thought he was just stalking me, flying around (he was wearing enchanted armor as well, but he drank invisibility potion, so I couldn't see his name tag). Well, I went outside to check on Otaku, and he just got near us, and threw a potion at us. I thought nothing of it, until she started whimpering, like when they get splashed with a poison potion. I decided to try to put her down (her tail was spinning), but sHE FREAKING COULD NOT. TAKE. DAMAGE! I tried everything! I've tried giving her healing potions, I've tried bows and swords (enchanted and non-enchanted), I've tried extra poison, meat, everything! I've even had a lot of people TPA to me to try to kill her! Nothing! She's not taking any damage whatsoever! It may sound like a good thing, but it is the biggest nuisance I've ever encountered. The potion isn't even wearing off! I've messaged a player, but he couldn't do anything about it. I'm not lying! So a long story short, Otaku's now a baby wolf and she has hearts floating above her head, and now her tail is constantly spinning and there's nothing I can do about it.
ANY SUGGESTIONS?

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