One of the two Tsukinami Village Gym leaders' (Hinata's) Whimsicott is the only Pokemon that can learn Spiky Shield. The only way a player can use the move themselves is to use Transform/Sketch on said Whimsicott
Spiky Shield is a Grass-type move, which protects the user from all effects of moves that target users during the turn it is used, including damage, excluding that from weather conditions and prior status ailments. Additionally, if Spiky Shield blocks an attack that would make contact with the user, the attacker suffers damage equal to ⅛ of its maximum HP. However, if an attack is blocked by Spiky Shield, the effects of the user's Rocky Helmet and/or Rough Skin will not activate.
If Sucker Punch is used on a Pokémon that has used Spiky Shield, the move fails and the Pokémon does not take damage. Feint and Phantom Force both bypass Spiky Shield and lift Spiky Shield's protection for the rest of the turn.
Spiky Shield is unable to defend against any of the following moves:
Pokémon that learn Spiky Shield
None; only Hinata's learns it.