this.addAbility(new EntersBattlefieldTappedAbility());
// {1}, {tap}: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle your library. Return Thawing Glaciers to its owner's hand at the beginning of the next cleanup step.
Ability ability = new SimpleActivatedAbility(Zone.BATTLEFIELD,
new SearchLibraryPutInPlayEffect(new TargetCardInLibrary(new FilterBasicLandCard()), true, Outcome.PutLandInPlay), new GenericManaCost(1));
ability.addCost(new TapSourceCost());
ability.addEffect(new CreateDelayedTriggeredAbilityEffect(new AtTheBeginOfNextCleanupDelayedTriggeredAbility(new ReturnToHandSourceEffect(true))));
this.addAbility(ability);
}