@horhik The program used for these animations is glitchcat (https://github.com/kuviman/glitchcat), on the Arch Linux Repository you can find it as the glitchcat-git package. I just send a random ASCII art to the program in the last line of ~/.zshrc (or ~/.bashrc if you prefer bash) and it automatically displays the animation on start.
To create the ASCII art I used a program called Jave, which can take an image and create a text version of it.

@lmedinar Thanks

@x Here it is, I drew it myself. It is quite small because in my system it is expanded using an external wallpaper setter (xrootgif), so you may need to expand it using something like gimp.
The penguin suit idea came from the GNU/Linux mascot Tux.

@lmedinar thank you so much! I love it :D

@liebook it is achieved using a program called glitchcat (just like cat, but with glitch animations), I found it in the AUR as glitchcat-git.

You can also find it on github: https://github.com/kuviman/glitchcat

After the install I just included this at the end of my .zshrc file (it could be in .bashrc instead y you use bash):

glitchcat -a 100 -d 600 -f 400 -g 100 -m HomoGlyphs ~/Imágenes/ASCII/lain/lain$(azar 1 7)

The “azar” function basically takes a random number between an interval, which I use to pic a random ASCII art text in a folder. It is defined as follows inside .zshrc:

function azar(){    minimo=$1    maximo=$2    diferencia=maximo-minimo+1    echo $(((RANDOM % diferencia) + minimo))}

@lmedinar thanks, that's awesome