The mystery plant (which may be Arum maculatum) is aging—no surprise, and the spathe* is now drying and becoming less delicate. Compare to four days ago….
KW, over at ababsurdo, has a picture of an actual JITP (jack-in-the-pulpit).
* For enquiring minds, the spathe is the hood-like bract, which grows “around” the yellow spadix, the spiky inflorescence.
Comment: yesterday’s tomatoes…yup, visibly larger today.