Viking Warcry

As an additional cost to cast Viking Warcry, tap
three untapped creatures you control.
Viking Warcry deals 3 damage to target creature
or planeswalker. If you control a Viking, Viking
Warcry deals 3 additional damage to that target.
"Amidst the clash of swords and the roar of the
longship's horn, the Vikings rally for glory."