Aleksey Shiishak Ustinov, also known as silt — is a Russian esports athlete, specializing in the fourth position support in Dota 2.

On the professional scene, Shiishak debuted in 2016, participating in the FACEIT league. In December 2023, he joined the team Winter Bear CIS, with which he placed sixth at the Winline Insight Season 4 tournament.

In the spring of 2024, Aleksey joined ASAKURA to participate in the qualifiers for the Elite League. The team successfully passed the open stage, but before the start of the closed qualifiers, Shiishak left the lineup.

In May, Alexey joined Team Secret and tried to qualify for Riyadh Masters 2024 and The International 2024, but was unsuccessful, after which Shiishak moved to Nemiga Gaming.