[X] My Assistant

[Jaxek]

This particular Tyranitar is for the Battle Hall, so I want him to cover as many weaknesses as possible. His current moves are Thrash, Earthquake, Rock Slide, and Crunch. I thought I would replace Thrash with another strong physical attack like an elemental punch or Aqua Tail. Any suggestions?

[Kumo987]

I'm pretty sure tyranitar can learn screech. It is an EXCELLENT defense stat lower. Tyranitar has excellent physical strength, so i'd go with that

[Hoolo]

If you went for an all-out physical moveset, either Aerial Ace or Ice Fang.
I regard Ice Fang over Ice Punch, even though its Base Power is 10 lower, it has the chance of making the opponent flinch if you're faster.
If you train(ed) that Tyranibeast well, it should outrun a few things, so it would be very helpful.

Aerial Ace is wonderful on things like Breloom and Heracross, who can exploit your 4x weakness. It also works well on Fighting types in general.

If you don't feel bad about having a status move, either Screech or Thunder Wave.
Screech for the reasons Kumo said before, and Thunder Wave for paralysis and slowing down the opponent more, with chance of them not hitting you.
Though Thunder Wave doesn't work on Electric-types, most of those won't need to be subject to it with Earthquake in your set.

[Cuish]

I'd replace Thrash with Aerial Ace. So at least you'll have something that's good aganist Bug, Grass and Fighting. As a bonus, it will never miss.

[monster415]

Actually I would replace Rock Slide with Ice Punch.

Rock Slide: covers Bug/Flying/Fire
Ice Punch: covers Ground/Flying/Dragon/Grass


And as people have mentioned, replace Thrash with Aerial Ace

[Hoolo]

Actually I would replace Rock Slide with Ice Punch.

Rock Slide: covers Bug/Flying/Fire
Ice Punch: covers Ground/Flying/Dragon/Grass


And as people have mentioned, replace Thrash with Aerial Ace

I also very much like this one. You'll have Ground, Ice, Dark and Flying, providing coverage to:
Fire, Electric, Poison, Rock, Steel
Grass, Ground, Flying, Dragon
Psychic, Ghost
Bug, Grass (again), Fighting.

Which makes for a total of 13 types, it seems.
The only ones missing are Dark, Ice, Water and Normal, of which three are weak to Fighting, so theoretically you switch it around a bit and go for a Fighting move as well, hmm.

[monster415]

You are forgetting that t-tar is resistant to normal and dark, so no worries there. Sandstream, which summons sandstorm, gives a 30% Sp. Def Boost to Rock types to help counter Sp. Attack water and ice types.

But then again, Brick Break instead of Crunch works too, since Ghost and Psychic types are pretty much useless against it, unless they are running Focus Blast, in which case luck is your best friend regardless .