It's not a glitch. When the Bair clanked with the Gordo it canceled out its hitbox. If your Bair was stale the Gordo would have clanked with and hit through your Bair. I've done this a few times with Dair and Uair myself. As long as the gordo won't do 9+ more damage than the aerial, it won't break through.Good to know,
off topic but I was playing a DDD the other day, he threw a Gordo and i did my bair, it hit my bair and kept moving, it passed through me and did not deal damage or any knockback, it just phassed through me.
Glitch? Tactics against gordo? Useless?
Also the strongest move DK has is a grounded sweetspotted 9 punch (the backhand of death). The next strongest is a sweetspotted fully charged Fsmash (the sweetspot is close to DK but not inside him). I don't remember whether or not grounded 9 punch or a regular fully charged Fsmash (his hands/forearms) is third place.