Why did a Ground type move hit a Flying type Pokemon?

Question

OK, Pokemon X, I'm battling a Hawlucha, my Tyrunt used Bulldoze and it worked on him (Which surprised me cause its Fighting and Flying type), so I just thought it must be because it is mainly Fighting type, then my Tyrunt fainted so I sent out Gyarados and used Bulldoze, but it said it doesn't affect him?? WTF is with that, did my game just glitch with Tyrunt or what?

Answer 1

There are three possibilities, one more likely than the others.

The first possibility is that Gravity was in effect, and wore off the same turn.
The second is that the opposing Hawlucha used Roost that turn, which takes away Flying typing for a turn. This is the most likely.
The third is that it was a glitch, however this is very unlikely.

Comments

Yeah I think it may have been roost, thanks that was really annoying me!!

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@Charizardisbae. How about selecting this as the answer to thank the person who wrote it.
Thanks @crimson didn't know roost disables fly.