Hippopotamus

You gain a +4 bonus on the following checks and saves: Swim checks made to resist nonlethal damage from exhaustion; Constitution checks made to continue running; Constitution checks made to avoid nonlethal damage from a forced march; Constitution checks made to hold your breath; Constitution checks made to avoid nonlethal damage from starvation or thirst; Fortitude saves made to avoid nonlethal damage from hot or cold environments; and Fortitude saves made to resist damage from suffocation.

You may sleep in light or medium armor without becoming fatigued.

You get a +4 bonus on initiative checks.

You can choose to take a –1 penalty on all melee attack rolls and combat maneuver checks to gain a +2 bonus on all melee damage rolls. This bonus to damage is increased by half (+50%) if you are making an attack with a two-handed weapon, a one handed weapon using two hands, or a primary natural weapon that adds 1-1/2 times your Strength modifier on damage rolls. This bonus to damage is halved (–50%) if you are making an attack with an off-hand weapon or secondary natural weapon. When your base attack bonus reaches +4, and every 4 points thereafter, the penalty increases by –1 and the bonus to damage increases by +2. You must choose to use this feat before making an attack roll, and its effects last until your next turn. The bonus damage does not apply to touch attacks or effects that do not deal hit point damage.

You get a +3 bonus on all checks involving the chosen skill. If you have 10 or more ranks in that skill, this bonus increases to +6.