Shared Animosity
Enchantment
Whenever a creature you control attacks, it gets +1/+0 until end of turn for each other attacking creature that shares a creature type with it.
"It is the nature of souls that they burn more brightly together than apart." —Vessifrus, flamekin demagogue
Chuck Lukacs
Rulings
This ability counts creatures, not creature types. For example, if you attack with five creatures — an Elf Shaman, an Elf Warrior, a Goblin Shaman, an Elemental, and a creature with all creature types — the ability will trigger five times. Those creatures will get +3/+0, +2/+0, +2/+0, +1/+0, and +4/+0, respectively.
(wotc • 2008-04-01)
In a Two-Headed Giant game, only creatures you control trigger the ability and get the bonus, but your teammate's attacking creatures are included in the calculation of those bonuses.
(wotc • 2008-04-01)
Rulings
This ability counts creatures, not creature types. For example, if you attack with five creatures — an Elf Shaman, an Elf Warrior, a Goblin Shaman, an Elemental, and a creature with all creature types — the ability will trigger five times. Those creatures will get +3/+0, +2/+0, +2/+0, +1/+0, and +4/+0, respectively.
(wotc • 2008-04-01)
In a Two-Headed Giant game, only creatures you control trigger the ability and get the bonus, but your teammate's attacking creatures are included in the calculation of those bonuses.
(wotc • 2008-04-01)