Quarrelwood Wurm

Hexproof
When Quarrelwood Wurm enters the battlefield,
or attacks, you get {e}.
Whenever Quarrelwood Wurm is attacking, you
may pay {e}{e}{r}. If you do, it gets +2/+1 and
Trample until end of turn. You may activate this
only per combat.
"Metallo-crystaline scales build energy as they coil
and move, crackling and repelling magic."