Ralsei, Dark Prince

Vigilance
Whenever a creature becomes tapped by a source
that you control, gain control of that creature
until it becomes untapped.
{2}{g} Search your library for a land card and put
onto the battlefield tapped, activate this ability
only if you control 5 creatures you don't own.
{2}{u}{t} Tap target creature it doesn't untap while Ralsei is in play.