Quad tens must beat. Both players must use their two hole cards. In texas holdem you're dealt two cards and after several rounds of betting you make a 5 card hand from your two "hole" cards and 5 community cards. An example of a bad beat is if player one(P1) is dealt 10h/10c and player two (P2) is dealt Js/Jd and the community cards are 10s, 10d, Jh, Jc, 3c; here quad tens is beat by quad jacks. Another example would be, P1 is dealt 2s/3s and P2 is dealt Ah/Ac and the community cards come out As, 4s, 5s, Ad, 9d; here Quad Aces is beaten by a straight flush.