According to card text, Mind Numb is burnt during the next untap
phase of the controller of the vampire who played it.
MIND NUMB CARD TEXT
Mind Numb: Action, Presence, 1 blood
(D) Put this card on any untapped vampire. Tap that vampire; he or she
does not untap during his or her controller's untap phase. Burn this
card at the beginning of your next untap phase. (S) As above, with +1
stealth.
Greetings,
Damnans
It is burnt at the untap phase of the Methuselah who controls the minion
it is on. It is a minion card (not a master card) -> it is controlled
by the controller of the minion it is on.
--
LSJ (vte...@white-wolf.com) V:TES Net.Rep for White Wolf, Inc.
Links to revised rulebook, rulings, errata, and tournament rules:
http://www.white-wolf.com/vtes/