Jhanti Skymaster

When Jhanti Skymaster or another creature you control with
flying enters the battlefield under your control you may pay
{w/u}, if you do, tap target creature, it does not untap
during its controllers next untap step.
"Jhanti is unknown by Dominaria, we live above the clouds,
in a world hidden by illusion and the endless sea of sky, but
some clever enough have learned to use its magic, the skymasters
go beneath the clouds to apprehend the knowledge stealers" -Kayla,
Skymaster Chief