When you're publishing a gaming supplement, you probably want to include statistics about the stuff you made, so that players can use it in their games.
Statistics are most readable when they're in tables, because you can look for the name of the item you want, then go across to the column of the statistic you want. But tables require a lot of space. That's a problem when you're publishing in a magazine and only have two pages.
So a lot of writers just put the stats in regular text. Usually this takes a format like "Statistic name: Value", repeated until all of the statistics have been described. Often there aren't any line breaks, and the stats will look like a wall of text - or a "block," if you will.
Stat blocks are also much less work to format than tables are, so they are the preferred stat-giving format of lazies and people who don't want to bother the editors.
Mordacicus Stats: Height = 6’2”, Weight = 211 lbs., Age = 22, Sexuality = Hetero, Eyes = Brown, Hair Color = Brunette, Hair Thickness = Thick, Hair Length = middle of the back, Hair Type = wavy, Most Attractive Feature = chest, Most Repulsive Feature = hands, level 3 mercenary, Skin Color = tan, Physical Fitness = 111, Strength = 182, Bodily Attractiveness = 123, Health = 131, Facial = 98, Vocal = 148, Kinetic = 111, Rhetorical = 86, Hand-Eye = 152, Agility = 124, Reaction Speed = 136, Enunciation = 92, Language = 97, Math = 107, Analytic = 108, Spatial = 112, Drive = 103, Intuition = 109, Common Sense = 73, Reflection = 84, LP = 32, CA = 33, PP = 07, Disposition = NI, Temperament = CM, Languages = Sapian, Equipment = Goring Zweihander + 6, dagger, chainmaille hauberk, (4-in-1), and 544 s.p.
A stat block from microlite20
Gideon, Rogue 4. STR 14(+2), DEX 16(+3), MND 15(+2), hp 28, AC 15 (Comabt Coat), +5 shortsword, 1d6+2 and +5 dagger 1d4+2. Subterfuge +8, all others @+5. Treasure: shortsword, combat coat, dagger in a locked chest.
Stat blocks from Advanced Dungeons & Dragons
- Gorharg, half-orc thief; (AC: 7, MV 9", 5th level thief, hp 24, #AT 1, D by weapon type, AL LE. S 13, I 17, W 1O, D 14, C 13, Ch 11. He wears leather armor +1, and carries a sling, a longsword +1, and a dagger +1.
And for groups of monsters/mooks:
- Orcs, (8; AC: 5, MV 9", HD 1, hp 7,7,7,5,5,4,4, 4, #AT 1, D by weapon type). They wear chain mail and carry longbows and flails, plus each has 2-40 gp.