I would choose a nettle, as Admiral Butterflies do. There flowers aren't extravagant but the poison tipped spines are very good protection.
Which nettle you may ask (as there are many)
Ideally Urtica sykesii for its beautiful triangular leaves perfectly embellished with triangular edges which itself have beautiful spikes (one of my favorite plants).
For added protection the most dangerous nettle Urtica ferox a nettle so big it has become a woody tree with thick spikes as long as your nose, loaded with enough poison to kill a dog or leave a man limp for weeks (I would make sure no dogs are harmed). The beautiful red admirals favorite choice.
If monofloral relationships require too much commitment, why not consider joining a polyfloral rainbow butterfly community. Maybe polyfloral is the way to go.
Are you asking about effective plantings to attract butterflies? In that case we need more information like your approximate location and hardiness zone. Or is this a whimsical question.
It’s a top secret human experiment to see how different people interpret it.
If you’re into botany/entomology, this is the time and place for you to shine. If you’re out for the giggles, that should work equally well. Other options are also equally valid.
As a butterfly I would recommend everyone plant clovers in their lawn. They are mowable, nitrogen fixing and were common in all grass mixes before broad leaf herbicides were common. They provide the surrounding grass and themselves with their own nitrogen as well provide some bee food. White dutch clover should be available most places and Flawn has a nice three color mix for all my clover needs.