Hann's Luku, Neverending Sands

({t}:add {w}.)
When Hann's Luku, Neverending Sands enters
the battlefield you may tap it, If you do, exile
target creature with converted mana cost 2 or
less until it leaves the battlefield.
At the beginning of your upkeep, you may
pay {w} , If you don't, sacrifice Hann's Luku,
Neverending Sands.