Empress Xpiayoc of Tocatli

Dinosaur spells you cast have convoke.
Whenever a Dinosaur enters the battlefield, if
seven or more creatures convoked it, untap those creatures. Until end of turn, those creatures gain trample and get +X/+X until end of turn, where
X is the convoked creature's power.
"The Sun Empire raise and train these animals. In
turn, they gift us the vigor and gallantry we could
never achieve alone."