Target creature you control gets +1/+0 until end of turn and can't be blocked this turn.
Overload(You may cast this spell for its overload cost. If you do, change its text by replacing all instances of "target" with "each.")
4/15/2013 If you don’t pay the overload cost of a spell, that spell will have a single target. If you pay the overload cost, the spell won’t have any targets.
4/15/2013 Because a spell with overload doesn’t target when its overload cost is paid, it may affect permanents with hexproof or with protection from the appropriate color.
4/15/2013 Note that if the spell with overload is dealing damage, protection from that spell’s color will still prevent that damage.
4/15/2013 Overload doesn’t change when you can cast the spell.
4/15/2013 Casting a spell with overload doesn’t change that spell’s mana cost. You just pay the overload cost instead.
4/15/2013 Effects that cause you to pay more or less for a spell will cause you to pay that much more or less while casting it for its overload cost, too.
4/15/2013 If you are instructed to cast a spell with overload “without paying its mana cost,” you can’t choose to pay its overload cost instead.
3/14/2017 The set of creatures that gets +1/+0 from an overloaded Teleportal is determined as the spell resolves. Creatures you begin to control later in the turn won’t get +1/+0. However, because the second part of Teleportal’s effect doesn’t change the characteristics of any permanents, the set of creatures that can’t be blocked is constantly updated. Any creature you control at the moment blockers are chosen can’t be blocked.