Card name: Gideon, Ally of Zendikar
Mana Cost: CMC2Color WColor W
Converted Mana Cost: 4
Types: Planeswalker — Gideon
Card Text: +1: Until end of turn, Gideon, Ally of Zendikar becomes a 5/5 Human Soldier Ally creature with indestructible that's still a planeswalker. Prevent all damage that would be dealt to him this turn.

0: Create a 2/2 white Knight Ally creature token.
−4: You get an emblem with "Creatures you control get +1/+1."

Loyalty: 4
Expansion: BFZM Battle for Zendikar
Rarity: Mythic Rare

Gideon, Ally of Zendikar
Card rulings (?)
2015-08-25 Gideon's first ability doesn't count as a creature entering the battlefield. Gideon was already on the battlefield; he only changed his types. Specifically, your rally abilities won't trigger. (Of course, Gideon's second ability will cause rally abilities to trigger.)
2015-08-25 If Gideon becomes a creature the same turn he enters the battlefield, you can't attack with him or use any of his {T} abilities (if he gains any).
2015-08-25 Gideon's first ability causes him to become a creature with the creature types Human, Soldier, and Ally. He remains a planeswalker with the planeswalker type Gideon. (He also retains any other card types or subtypes he may have had.) Each subtype is correlated to the proper card type: planeswalker is only a type (not a creature type), and Human, Soldier, and Ally are just creature types (not planeswalker types).
2015-08-25 If damage that can't be prevented is dealt to Gideon after his first ability has resolved, that damage will have all applicable results: specifically, the damage is marked on Gideon (since he's a creature) and that damage causes that many loyalty counters to be removed from him (since he's a planeswalker). Even though he has indestructible, if Gideon has no loyalty counters on him, he's put into his owner's graveyard.
Emblem Gideon

Emblem from Gideon, Ally of Zendikar