// Hexproof
this.addAbility(HexproofAbility.getInstance());
// {3}{B}: Until end of turn, Xathrid Slyblade loses hexproof and gains first strike and deathtouch.
Effect effect = new LoseAbilitySourceEffect(HexproofAbility.getInstance(), Duration.EndOfTurn);
effect.setText("Until end of turn, {this} loses hexproof");
Ability ability = new SimpleActivatedAbility(Zone.BATTLEFIELD, effect, new ManaCostsImpl("{3}{B}"));
Effect effect2 = new GainAbilitySourceEffect(FirstStrikeAbility.getInstance(), Duration.EndOfTurn);
effect2.setText("and gains first strike");
ability.addEffect(effect2);
Effect effect3 = new GainAbilitySourceEffect(DeathtouchAbility.getInstance(), Duration.EndOfTurn);