Velkhana, Iceborne Wyvern

Whenever a nonsnow creature attacks you or a planeswalker you control, put an ice counter on
it. If it already has an ice counter on it, destroy all enchantments attached to it instead.
Creatures with ice counters on them don't untap during their controller's untap step. At the
beginning of each other players' end step, you
may put an ice counter on target creature that
player controls if they control another creature
with an ice counter on it.