How can I change an embed footer depending on the array it is ubicated?

I'm trying to make a roleplay bot command where the user tags another person and then the bot has to say something and then it appears a random image and the footer must say which is the character from the picture, I want to do even with more arrays, one for each character maybe but I don´t know if I am complicating my self a lot, and even though what I have done is not working and I don't know why.

#Example for  StackOverflow
@bot.command()
async def roleplaying (ctx, user:discord.User):
    nyan_cat= ["https://1.bp.blogspot.com/-XBOvQhJ4e3E/YINVEJxvRyI/AAAAAAAAATo/S-PlEpwNLzs250tmpWEzkmiLt_Fbeu5UACLcBGAsYHQ/s476/Nyan%2Bcat.gif"]
    pikachu = ["https://c.tenor.com/-VYWaSmWx2QAAAAC/thunderbolt-pikachu.gif"]

    random_image= random.choice([nyan_cat,pikachu])
    avc = discord.Embed(
        title= "",
        description= f"**{ctx.message.author.name}** wants **{user.name}** to watch the picture ❤️",
        colour=0x0101df
        )
    if random_image == nyan_cat:
        avc.set_image(url=random_image)
        avc.set_footer(text= "Character: Nyan Cat.")
        await ctx.send(embed=avc)
    elif random_image == pikachu:
        avc.set_image(url=random_image)
        avc.set_footer(text= "Character: Pikachu.")
        await ctx.send(embed=avc)

Solution

I changed your code a little and for me it's working fine like this:

@bot.command()
async def roleplaying (ctx, user:discord.User):
    nyan_cat= "https://1.bp.blogspot.com/-XBOvQhJ4e3E/YINVEJxvRyI/AAAAAAAAATo/S-PlEpwNLzs250tmpWEzkmiLt_Fbeu5UACLcBGAsYHQ/s476/Nyan%2Bcat.gif"
    pikachu = "https://c.tenor.com/-VYWaSmWx2QAAAAC/thunderbolt-pikachu.gif"

    random_image= random.choice([nyan_cat, pikachu])
    avc = discord.Embed(title= "", 
                        description= f"**{ctx.message.author.name}** wants **{user.name}** to watch the picture ❤️", 
                        colour=0x0101df)
    if random_image == nyan_cat:
        avc.set_image(url=random_image)
        avc.set_footer(text= "Character: Nyan Cat.")
        await ctx.send(embed=avc)
        
    elif random_image == pikachu:
        avc.set_image(url=random_image)
        avc.set_footer(text= "Character: Pikachu.")
        await ctx.send(embed=avc)

EDIT: Feature added multiple gifs in array. Pretty sure it's not the best way to do it, but it works.

@bot.command(name='roleplaying')
async def roleplaying(ctx, user:discord.User):
    
    nyan_cat= [ "https://1.bp.blogspot.com/-XBOvQhJ4e3E/YINVEJxvRyI/AAAAAAAAATo/S-PlEpwNLzs250tmpWEzkmiLt_Fbeu5UACLcBGAsYHQ/s476/Nyan%2Bcat.gif", "https://icegif.com/wp-content/uploads/nyan-cat-icegif-5.gif" ]
    pikachu = [ "https://c.tenor.com/-VYWaSmWx2QAAAAC/thunderbolt-pikachu.gif", "https://c.tenor.com/P9pPZ1prRCMAAAAd/pokemon-pikachu.gif" ]

    random_char = random.choice(['nyan_cat', 'pikachu'])
    if random_char == 'nyan_cat':
        random_image = random.choice(nyan_cat)
    elif random_char == 'pikachu':
        random_image = random.choice(pikachu)
    
    avc = discord.Embed(title= "", 
                        description= f"**{ctx.message.author.name}** wants **{user.name}** to watch the picture ❤️", 
                        colour=0x0101df)
    if random_char == 'nyan_cat':
        avc.set_image(url=random_image)
        avc.set_footer(text= "Character: Nyan Cat.")
        await ctx.send(embed=avc)
        
    elif random_char == 'pikachu':
        avc.set_image(url=random_image)
        avc.set_footer(text= "Character: Pikachu.")
        await ctx.send(embed=avc)