Tricky van Baalen was the youngest and the smartest of the Van Baalen brothers.
Tricky worked for his brothers Gregor and Bram, finding and processing salvaged spaceships. Although made captain by their father, he suffered an accident in which he lost his eyes, his voice, and his memory. He was fitted with synthetic eyes and a partially electronic-sounding voice box; unable to replace his memory, his brothers instead convinced him that he was in fact an android.
When the brothers came across the Doctor's TARDIS they used their magno-grab to haul it in as salvage, causing damage to its engines and fuel to leak. The Eleventh Doctor, having been thrown free from the TARDIS convinced the Van Baalen Bros. to enter the TARDIS under the promise of the "salvage of a lifetime." Once on board, the Doctor locked the doors, trapping the brothers inside the TARDIS and forcing them to help find Clara under the pretence of the TARDIS' fictitious self destruct sequence.
When the TARDIS' fuel rods began to break apart, Tricky became trapped by a metal beam, and Gregor refused to cut his arm, confessing that he was in fact human. As they reached the Eye of Harmony, Tricky pushed a time zombie off of the walkway, almost falling off himself. The Doctor warned Gregor and Tricky not to touch lest time reasserted itself, but Gregor pulled Tricky to safety, and they fused, taking on the form of one of the zombies.
This timeline was undone by the Doctor. In the new timeline the TARDIS briefly appeared on the salvage ship's monitors before quickly vanishing before it could be pulled in by the magno-grab field. In this timeline a photograph of the three brothers and their father remained intact (it had previously been torn to omit Tricky as part of his brothers' ruse), and Gregor treated Tricky with more respect. (TV: Journey to the Centre of the TARDIS)
Before the salvage accident which cost Tricky his sight, voice and memory, he was described as the smartest of the van Baalen brothers, and the one who was best suited to be captain of their salvage ship. He was easily the most compassionate brother, being the first to realise that the TARDIS was suffering and often acted as Bram and Gregor's consciences. He also warned the Doctor that if he went into the TARDIS to rescue Clara he would be poisoned and was the only brother who was willing to help without asking for anything in return. When Bram was killed by Clara's time zombie, the Doctor realised that Tricky was more "cut up" about it than Gregor was.
After his amnesia, Tricky thought he was an android due to his synthetic eyes and voice box and was convinced that he could not feel pain or fear, to the point where he believed that if Gregor cut off his arm, he wouldn't feel it. Tricky was outraged when he realised that his brothers had lied to him, but the Doctor reminded him that Gregor still had a scrap of decency since he had refused to slice off his arm. Tricky was brave enough to fight against one of the Time zombies in order to protect the Doctor, Clara and Gregor and almost fell into the Eye of Harmony in the process. After the Doctor rewrote time, the three brothers appeared to have become closer than before, despite being unable to remember their adventure. (TV: Journey to the Centre of the TARDIS)