All praise is due to Allah. May Allah's peace and blessings be upon our Prophet Muhammad, his family, and companions.
Wa alaykum salaam wa rahmatullahi wa barakatuhu
To answer your question I say:
The problem with these clothes is that they make a person imitate the animal whose shape the clothes take. Comparison to animals was only mentioned in the Qur'an in the context of being censured, whether that was in relation to acts of worship, or other actions and conditions. Allah the Exalted said, " And recite to them, [O Muhammad], the news of him to whom we gave [knowledge of] Our signs, but he detached himself from them; so Satan pursued him, and he became of the deviators. And if We had willed, we could have elevated him thereby, but he adhered [instead] to the earth and followed his own desire. So his example is like that of the dog: if you chase him, he pants, or if you leave him, he [still] pants. That is the example of the people who denied Our signs. So relate the stories that perhaps they will give thought." [al-A'raf: 175-176]. Allah also said, "The example of those who were entrusted with the Torah and then did not take it on is like that of a donkey who carries volumes [of books]. Wretched is the example of the people who deny the signs of Allah . And Allah does not guide the wrongdoing people" [al-Jumu'ah: 5]. Al-Bukhari and Muslim transmitted from the hadeeth of Abdullah ibn Abbas (may Allah be pleased with him) that he said, "The Prophet (peace be upon him) said, "One who takes back his gift (which he has already given) is like a dog that swallows its vomit" [al-Bukhari (2589], and Muslim (6622). A narration in Saheeh Muslim (498) from Aishah (may Allah be pleased with her) stated that she narrated, "and he forbade people to spread out their arms like a wild beast," that is in prayer. These and similar texts indicate that similitude to animals is generally censured. Therefore, the least that can be said about these clothes which are have the shape of animals is that they are detested. However, some scholars stated that imitating animals is prohibited at all times because of the texts which censure animals. And Allah knows best.
Shaykh Khalid al-Mosleh