Rockhoof vs Sylvia: who would win?

Rockhoof favored — Slight edge (~55%)

Rockhoof · My Little Pony · Base

Tier

10-C, up to 6-B

Attack Potency

Below Average Human Level, up to Country Level

Speed

Subsonic

Durability

Below Average Human Level, up to Country Level

Sylvia · Star Trek · Base

Tier

10-C, up to HIGH 6-A

Attack Potency

Below Average Human Level, up to Multi-Continent Level

Speed

Below Average Human, up to Superhuman

Durability

Below Average Human Level, up to Multi-Continent Level

A heuristic estimate from normalized VS Battles Wiki stats: tier, attack potency, speed and durability.