Gliscor vs Planetar: who would win?

Gliscor favored — Slight edge (~55%)

Gliscor · Pokémon · Base

Tier

LOW 7-B, up to HIGH 7-A

Attack Potency

Large Mountain Level

Speed

Massively Hypersonic+, up to Ftl

Durability

Small City Level, up to Large Mountain Level

Planetar · Dungeons & Dragons · Base

Tier

LOW 7-B

Attack Potency

Small City Level

Speed

Relativistic+, up to Ftl+

Durability

Small City Level

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