Now that Teenage Mutant Ninja Turtles has been out for nearly a week, Wizards has posted a rules and Oracle update to Daily MTG. The rule changes are minor but do impact players confused by the timing in TMNT’s sneak mechanic. Now that UB sets are Standard-legal, it’s vitally important that the rules of each mechanic are fully understood by players. 

Rule Changes

Adjustments were made to rule 702.190 and its subrules to fully define Sneak as "Any time you could cast an instant during your declare blockers step, you may choose to pay [cost] and return an unblocked creature you control to its owner's hand rather than pay this spell's mana cost." Additionally, the rule change clarifies that the permanent entering using the Sneak cost will be attacking the same target as the creature that was returned in paying for the spell. Whatever player or planeswalker that creature was attacking will be the new permanent’s target as well.

Minor rule changes were also made to 506.3d and 508.4d, creating new subrules for instances where a creature enters attacking after the declare blockers step. Functionally, it doesn’t change anything but rather removes the rule from the ninjutsu keyword to a more generic combat rule so that cards without ninjutsu have no gray area surrounding the function of the rule.

Rule 508.4 also received a minor clarification to make it clear that “If a creature is put onto the battlefield attacking, it remains an attacking creature until it is removed from combat or the combat phase ends, whichever comes first.”

Lastly, definitions were inserted into the rules to define the following:

• Mutagen tokens
• Partner — Character Select (added to the list of partner abilities)
• Utrom creature type
• Disappear ability
• Sneak keyword

Oracle Updates

Two Oracle updates were made in this announcement. One functionally changes a card while the other only clarifies what was already intended. The first of these updates affects Leonardo, Worldly Warrior.

Under the old text, Leonardo costs 1 less to cast for each creature you control. That’s still true, but now it’s under the header of Affinity for creatures. This is functionally a card errata, as before it didn’t interact with the Affinity keyword at all. Now spells that check for affinity will clock Leonardo’s Affinity for creatures ability. The new text reads “Affinity for creatures (this spell costs 1 less to cast for each creature you control.)”

The other less drastic Oracle update is for Arcade Cabinet. Previously, the second ability on it read “2, T, Sacrifice a token: Double the number of counters on target creature.” The card didn’t specify which counter and with Arcade Cabinet’s ETB trigger granting a +1/+1 counter on each of up to four target creatures, Wizards felt like it might be misinterpreted as doubling +1/+1 counters only. The new text fixes that by saying “2, T, Sacrifice a token: Double the number of each kind of counter on target creature.”

Wizards of the Coast has a rules page dedicated to every rule in Magic: The Gathering. The full rule text, including all of the recent changes, can be read there.