Childe, The 11th Harbinger

Double strike, haste, reach
When Childe, The 11th Harbinger deals lethal
damage to a creature, create and equip Riptide
to him, a legendary red Equipment artifact
token with "{r}, sacrifice this artifact: Add {u}. This artifact grants the equipped creature
+1/+1 and menace until the end of the turn."
"This opportunity is quite hard to come by.
Well then, amuse me!" - Childe