Using a modded potion such as fatal poison from mystic potions will respawn the dog on the bed like usual but then will continue damaging their health after respawning since the effect wasn't removed at respawn. I think it would be a good idea to remove all effect upon the respawn.

On a separate note:
I think it would also be a good idea to have a config to make it so it's one pet per bed as an option for players if this isn't already a thing.
(I haven't checked yet but I will when I'm on next)