Sorry if this question has already been answered, but this forum searching engine really sucks ! ^^'

Miserable Existence reads :

"R Commit : Before your opponent adds cards to their momentum, add X cards to your momentum from the same location your opponent would have added them instead. X equals the number of cards your opponent would have added."

Can I respond with this foundation during the End Phase to avoid my opponent's attacks to go into their momentum (supposing I have enough cards in my card pool to complete the effect) ?

Thank you for the future answers !

You may use it to gain momentum from your card pool if your opponent has attacks scheduled to go to their momentum, but if you "prevent" the addition of said attack using Miserable Existence, the game will try to resume clearing the card pool from the rightmost card - in other words, the attack will still be able to go to momentum.