The Bio-sludge launcher from UT: 2004. A small bio sludge blob sticks to terrain and acts like a mine. A large blob explodes into several smaller blobs.

(image of the alt fire mode)
Controls:
Pie Menu -> Gold Dig - Toggle weapon modes.
--Standard Mode--
Fire - Fire a single sludge blob. Hold for rapid fire.
--Secondary Mode--
(hold) Fire - Charge up device.
(release) Fire - Fire a large blob. Size depends on length of charge.
Credits:
CaveCricket48 - Coding, Lua Scripting, Sprites
Azukki - Glows
(whoever made UT) - Sounds