Veteran elf mage who burns away the battlefield fog and magnifies Dumplin' for the whole trench line to see.
As the trench line argues over whether the shapes in the fog are another illusion, an elf mage to Carl's right calls "Hang on" and strains through a spell. A portion of the swirling smoke dissipates, revealing the horde of Juiced Rot Sticker Behemoths.
His spell also carries a spyglass effect that zooms one creature big for everyone at once, almost like a boss battle notification: Dumplin', level 40, loaded with the Gurgles, Insanity, face-eating rabies, and a Truck Stop Boner Pill, owned by Cybernetician Yeller of The Reavers. Carl identifies him as one of the Veterans, and it is his single spell that gives the defenders any idea what is coming.
An elf mage straining visibly with effort as he casts, positioned on the trench line to Carl's right.
Veteran mage whose fog-clearing spyglass spell identifies the pet-bomb wave for the entire line.