14 Apr 2023
You can’t discard nonland cards, even if you want to.
14 Apr 2023
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.
14 Apr 2023
If there are one or fewer cards in your library, Borborygmos and Fblthp is put on the bottom of your library.
14 Apr 2023
Only the controller of Borborygmos and Fblthp can activate its last ability, and only if it’s on the battlefield.