Froslass is pretty. The design is very soft, it has nice little ice horns and seems to be made to look like a lady in a dress. 2/10 spook.

Danger is middling. Stats aren't super high, and the extra lore talks about how they will freeze people and use them as decorations. A little dangerous but not overly. 5/10.

Transform will be from a normal person (my favorite kind of transform). The vague human shape is still consistent. Humanoid, head is fairly well placed and sized, and the body is clearly designed to look like a kimono. Maybe a 6/10? While it is still fairly human-like, it also has some clear changes such as the arms extending from the head, and the curved bits.

Froslass is fairly simple. Frost and Lass. Works well for the idea though. 7/10.

Spooky? Rotom? I don't think so. Rotom is very much a cute Pokemon, but, they could be a little spooky because of their ability to inhabit electrical machines and cause them to be all wacky. 3/10 spook.

The danger of Rotom (in this form) is also not very high. Their stats aren't very high, and they have no interesting abilities in this form. While they are pure plasma, eg very dangerous, it never manifests as any real danger in the TCG, video games, or the show. 3/10.

The transform as always is difficult, especially since it is stated in the Pokedex that Rotom is composed of pure plasma (electricity). Because of that, I guess we could say they are a 10? Because going from literal electricity to an orange rounded being with blue eyes is pretty intense.

The name is WEAK. Rotom. Stealing from Arbok and Ekans. 2/10.

Giratina in Altered Forme is a little bit less spooky than in Origin Forme. They get stumpy little legs, and look a lot more like a natural animal. 4/10 spook.

The danger however does not share the same downgrade. Yes, Altered Forme is more tanky and less aggressive, but that bulk serves equally helpful in battle. 7/10 danger.

Who knows transformation honestly. Giratina was created by Arceus along with Dialga and Palkia, but was banished to the Distortion World because it was too violent. This would suggest Giratina has no original form beyond what they are. HOWEVER, there is the Origin forme, which I feel is fair to assume is the original look of Giratina. From that forme to this one, I would say we have a 6/10 transformation.

The name in full is Giratina (Altered Forme). I think Giratina is okay, however it really has no connection to the undead whatsoever, and Altered Forme sounds a little strange. 5/10 name.