Mystery plant misidentified as dragonfruit

"Cissus quadrangularis"

Scientific classification

1. Kingdom: Plantae
2. Clade: Angiosperms
3. Clade: Eudicots
4. Clade: Rosids
5. Order: Vitales
6. Family: Vitaceae
7. Genus: Cissus
8. Species: C. quadrangularis

Cissus quadrangularis is a perennial plant of the grape family. It is also known as veld grape, devil's backbone, adamant creeper, asthisamharaka, hadjod, pirandai, and patah tulang (Malay).Wikipedia

Description:

A perennial herbaceous climber. Stem thick, succulent, quadrangular, angles winged, constricted at nodes, glabrous or slightly downy, almost leafless when old. Tendril long, slender, simple. Petiole 6-12 mm long, glabrous. Leaves simple ovate, entire or cordate, serrulate dentate, or crenate-serrate, 3-lobed, terminal lobe triangular or sub-spathulate, subacute or ± cuspidate, membranous, glabrous on both sides, 3-5 x 5-3 cm; stipules ovate or cuneate, obtuse, deciduous. Inflorescence a compound umbelliform cymes, peduncle 1-2.5 cm long. Flower pink and white, 2 mm long, hypanthium cuplike, truncate or obsurely lobed, green, c. 2 mm broad. Petals 4,distinct, ovate-oblong, acute, hooded at apex, c. 1.5 mm long. Disc longer than the ovary. Ovary glabrous, style slender subulate, stigma small. Berry globose, red, succulent, very acidic, 6-10 mm in diameter, 1 seeded. Seed obovoid smooth, 4-8 mm across.Indian science publication

It is Cissus quadrangularis, a type of succulent often grown by cactus lovers, though it's actually a member of the grape family (Vitaceae). It produces these ivy like leaves at certain times, which it uses to try to climb or scramble over surrounding objects or plants. Does well in a hanging basket, when most of its growth will dangle downwards. Tolerates a fair bit of neglect, likes some sun, but more detailed instructions for care here https://www.logees.com/indoor/windowsill/veldt-grape-cissus-quadrangularis.html. Common names include Devil's backbone and veldt grape.

In maturity, it produces small yellow flowers followed by berry like fruits which turn red.

This plant is used medicinally and extracts from it in pill or powder form are often used by people with torn muscles or musculo skeletal damage, and in ayurvedic medicine. There's a fun blog about this plant here http://plantsarethestrangestpeople.blogspot.co.uk/2008/08/infomercial-pitchman-cissus.html