Blossemforth

This set of occurrences is created by 514.6:

simultaneously {
  place_card_on_bottom(X)
  place_card_on_bottom(Friend_with_pumped)
}

Blossemforth's replacement modifier replaces it with:

simultaneously {
  may_retire_and_pay_2AT(Blossemforth, play_at_problem(X), place_card_on_bottom(X))
  may_retire_and_pay_2AT(Blossemforth, play_at_problem(Friend_with_pumped), place_card_on_bottom(Friend_with_pumped))
}

Since there are now choices that must be made simultaneously, 801.1 applies. The
player chooses to use Blossemforth on Friend_with_pumped.

simultaneously {
  place_card_on_bottom(X)
  retire_and_pay_2AT(Blossemforth, play_at_problem(Friend_with_pumped))
}

710.3 comes into effect and Blossemforth doesn't apply to the
place_card_on_bottom because it already did. Actions resolved simultaneously.