Well, for starters, DIE_WHEN_VERMIN_BITE is only applicable to vermin, which can't really do anything else interesting, so that's out. And anything involving transformations is going to be really buggy unless it's something more-or-less standard. For instance, your idea could be useful if you want to make a creature that can TELEFRAG, having it transform into a creature that instantly boils away at the same time it turns another creature into a copy of itself (as if it teleported itself INTO the other creature, killing them)... but it could only do so once, since a transformed creature can't transform into something else.
That aside, you can use my teleport interaction if you want it, it's only convincing for short hops but it looks and functions good in both fortress and adventure. It's basically just a speed-boost combined with a tile change. The only problem being the occasional attack message spam if the creature attacks someone while in teleport mode (but the attacks won't do much, since its strength is reduced to nil while teleporting).