This is a set of multi-pens. These special big pens will write in whatever color you press the switch down for. (Switch colors correspond to ink colors most of the time) To put the tip back in, usually the top can be pressed. In this case, each pen has a fully 3D figure on the top with Sonic Tails or Eggman. They're all quite cute, done in a sort of SD style which probably lends durability as well. This is a great set of pens to collect, though they are uncommon.