1, NOTHING, NO, 35
1, VERSICOLOR, TREE, 35
3, DIVERSIPES, TREE, 35
4, AMAZONICA, TREE, 35
5, EMILIA, GROUND, 25
6, BOEHMI, GROUND, 25
7, SMITHI, GROUND, 25
8, METALLICA, SKY, 5
9, REGALIS, SKY, 5

SELECT *
FROM (
  SELECT id, name, type, chance
    , @value + 1 AS lowval
    , @value := @value + chance AS hival
  FROM tbl
  JOIN (SELECT @value := 0) AS foo) AS bar
JOIN (SELECT FLOOR(1 + RAND()*99) AS guesser) AS bar2
  ON guesser  BETWEEN lowval and hival;