Improved Grappler

You’ve developed the skills necessary to hold your own in close-quarters grappling. You gain the following benefits:

• You have advantage on attack rolls against a creature you are grappling.
• You may choose to grapple a creature as an opportunity attack.
• You can use your action to try to pin a creature grappled by you. To do so, make another grapple check. If you succeed, the creature is restrained and your speed becomes 0 until the grapple ends.
• While the creature is restrained, you may use your action to further restrain the creature. To do so, make another grapple check, this time with advantage. If you succeed, the creature is paralyzed and you are restrained. While in this special grapple, spells and effects that causes unwilling movement like thunderwave or shove must move both you and the creature for it to take effect. You can end this special grapple as an action.