Whiplash

When Whiplash enters the battlefield, you may
search your library for an artifact card, reveal it,
and put it into your hand. If you do, shuffle your library.
Whenever Whiplash enters the battlefield or
attacks, you get {e} (an energy counter).
{e}{e}{e}, {t}: Whiplash deals damage equal to its
power to target creature.
Landfall — Whenever a land enters the
battlefield under your control, you get {e}.