Tickle is a mutated tick found attached to a pipe in the Sewers, the one on a platform surrounded by waterfalls through the upper path from the furnace room. It claims that it was originally a normal tick, which gained sentience and human features when The Visitor came while it was feeding on a human. It provides an obstacle for the player by infesting a Furnace pipe, preventing the Furnace from being fully awoken. It must be removed by either killing it, or inviting it to infest Sam instead. It will sharply reduce Sam's max HP and STM while on him, but provides some unique skills in exchange. Tickle can be removed from Sam once acquired, either temporarily or permanently, by giving it to Henri. While Tickle still lives, you are able to purchase items from Tickle using Friendship Points. Friendship points can be obtained by feeding a party member's blood to Tickle, draining HP. A party member must have at least 50 HP to be chosen. Tickle will drain all health but 1 HP, and gives 1 Friendship Point for every 50 HP drained, rounding up.