Create wild, crazy, distorted, and weird text effects for Discord, game chats, and prank messages.
Zalgo (the dripping, corrupted look) is not a font. Unicode has a block of combining diacritical marks (U+0300 to U+036F) that attach to whatever letter comes before them: accents, tildes, underdots. A renderer draws them all, stacked. Put two above and two below each letter and you get the light glitch style; put ten and it climbs out of the line. The Zalgo Chaos style in the list attaches four random marks per letter. Because they are combining marks, the base letters are still there. Copy zalgo text into a search box and most engines will still match the plain word underneath.
Upside-down text is a lookup table. Unicode has no rotated Latin alphabet, so the tool borrows letters from other scripts that happen to look inverted (ɐ from the IPA for a, ǝ for e, ʇ for t) reverses the string, and swaps ? for ¿ and ! for ¡. About four letters have no convincing inverted form (o, x, s and z are their own upside-down), so they stay. Mirrored text simply reverses character order; there is no per-letter flip in Unicode. Both survive copying anywhere because they are ordinary characters, but neither is searchable or readable by a screen reader, so keep them out of anything that has to be found or heard.
Not on current platforms. Discord, Twitter and Instagram clip stacked marks to the line height, so heavy zalgo just looks dense rather than overflowing. Some older forums and game chats do not clip, which is where the overflowing look came from.
Some letters have no inverted look-alike in any script, o, x, s and z read the same either way, and there is no good flipped H or N. The tool passes those through rather than substitute something that reads wrong.
Poorly. It will either read each combining mark aloud or skip the word. Treat crazy styles as decoration for a headline or a nickname, never for a message someone has to understand.