Sonic Grenade

Attach: R
While this Weapon is attached to a Clash card you control, this Weapon gets, "Whenever the attached Clash card attacks, you may attach this Weapon to target Clash card defending player controls without paying that Weapon's attach cost."
While this Weapon is attached to a Clash card you don't control, this Weapon gets, "The attached Clash card can't attack or obstruct. During their Primary Phase, the attached Clash card's controller may pay two resources of any color to send this card to Oblivion. If they do, Clash cards they control get -2/-0 until their next turn."