Nyxborn Hydra

The scaling problem bestow was built to solve was rigidity: a bestow creature commits a fixed body to the enchantment, and when the host dies you get a fixed body back. Sizing it with X plus counters instead of a printed stat line reworks that math. The counters are the whole trick. Because they live on the permanent rather than on the aura relationship, they survive the transition: cast it for its bestow cost with a pile of counters, watch the enchanted creature die, and the hydra falls off as a creature carrying every one of those counters, still whatever size you paid for. Most bestow creatures shrink back to their creature stats when they unattach; this one keeps its investment either way, which means the X you sink in is never stranded on a chump-blocked host. That makes the two casting modes genuinely fungible rather than a hedge: pay X-plus-two-green to armor an attacker with reach and trample and a scaling boost, or hardcast it as a hydra of the same size that granted those keywords to itself. Reach and trample being conferred to the host, not just carried by the creature, is the detail that turns it into an evasive-and-defensive package rather than a raw stat stick. It is a clean synthesis of two green scaling ideas, hydras and counter-matters, run through a keyword that historically fought against permanence.