2023-04-14 : If there are one or fewer cards in your library, Borborygmos and Fblthp is put on the bottom of your library.

2023-04-14 : Only the controller of Borborygmos and Fblthp can activate its last ability, and only if it’s on the battlefield.

2023-04-14 : The first ability of Borborygmos and Fblthp triggers and goes on the stack without a target. If you discard one or more land cards, the second “reflexive” triggered ability will trigger. You’ll choose the target creature for that second ability at that time.

2023-04-14 : You can’t discard nonland cards, even if you want to.