Balloon Iron Crown isn't a reliable check to Gliscor, you don't do enough damage to the Sp.def variants and isn't that good at threatening max HP Gliscor.i agree. over in convergence, the om of the month, i've been using levitate iron crown to defensively check knockless lando-t (which in that format is basically just sd gliscor but better), and that got me thinking about balloon crown as a gliscor answer over here. the main issue i see with it is that if you lose your balloon you do just kinda get goobed by gliscor's most common attack, but you can at the absolute least outspeed and heavily chunk it and you stand to win the whole interaction if you do end up coming in on an sd or eq
252 SpA Iron Crown Tachyon Cutter (2 hits) vs. 244 HP / 228+ SpD Gliscor: 138-164 (39.2 - 46.5%) -- approx. 82.6% chance to 3HKO after Poison Heal
shave off 12% due to healing on same turn, not including possible Protect afterwards, and it's 27%-34% damage vs Sp.Def
252 SpA Iron Crown Tachyon Cutter (2 hits) vs. 244 HP / 0 SpD Gliscor: 200-236 (56.8 - 67%) -- approx. 2HKO after Poison Heal
Even this damage is negligible even without a Swords Dance boost since double knock still does great damage, you Knock it on switch in and again the following turn. Again shave off 12% this damage is 44%-55%, and then with Protect afterwards it's 32%-43%. This Pokémon healing the same turn it takes damage is actually so ridiculous lol.
Gliscor runs Knock Off on almost every set it has even on non Swords Dance, so it's not like this situation won't happen where Iron Crown ends up taking Knock Off damage. Also in the matchup against Swords Dance Gliscor it will just setup and threaten Iron Crown pretty badly.
+2 0 Atk Gliscor Knock Off (97.5 BP) vs. 0 HP / 0 Def Iron Crown: 268-316 (83.4 - 98.4%) -- guaranteed 2HKO