You flip a coin and receive a random effect: an attack boost or a defense boost.

Heads:
P. Atk. +6%
M. Atk. +10%
Atk. Spd. +5%
Cast. Spd. +5%

Tails:
P. Def. +7%
M. Def. +8%
Resistance to Debuff +10%
Healing Efficiency +10%